Is 21001 a prime number?

21 001 is an odd number, because it is not evenly divisible by 2.

Find out more:

• What is an even number?

A number is a perfect square (or a square number) if its square root is an integer; that is to say, it is the product of an integer with itself. Here, the square root of 21 001 is about 144.917.

Thus, the square root of 21 001 is not an integer, and therefore 21 001 is not a square number.

Anyway, 21 001 is a prime number, and a prime number cannot be a perfect square.

The square of a number (here 21 001) is the result of the product of this number (21 001) by itself (i.e., 21 001 × 21 001); the square of 21 001 is sometimes called "raising 21 001 to the power 2", or "21 001 squared".

The square of 21 001 is 441 042 001 because 21 001 × 21 001 = 21 001² = 441 042 001.

As a consequence, 21 001 is the square root of 441 042 001.

21 001 is a number with 5 digits.

The multiples of 21 001 are all integers evenly divisible by 21 001, that is all numbers such that the remainder of the division by 21 001 is zero. There are infinitely many multiples of 21 001. The smallest multiples of 21 001 are:

• 0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 21 001 too, since 0 × 21 001 = 0
• 21 001: indeed, 21 001 is a multiple of itself, since 21 001 is evenly divisible by 21 001 (we have 21 001 / 21 001 = 1, so the remainder of this division is indeed zero)
• 42 002: indeed, 42 002 = 21 001 × 2
• 63 003: indeed, 63 003 = 21 001 × 3
• 84 004: indeed, 84 004 = 21 001 × 4
• 105 005: indeed, 105 005 = 21 001 × 5
• etc.

• Preceding numbers: …20 999, 21 000
• Following numbers: 21 002, 21 003…

Nearest numbers from 21 001

• Preceding prime number: 20 983
• Following prime number: 21 011

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• 21 001 est-il un nombre premier ?