Number 640 is not a prime number. It is a composite number.

A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. We do not consider 640 as a prime number, because it can be written as a product of two smaller natural numbers (check the factors of number 640 below).

Number of factors: 16.

List of factors/divisors: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, 640.

Parity: 640 is an even number. It means it is divisible by 2 with no remainder.

Perfect square: no (a square number or perfect square is an integer that is the square of an integer).

Perfect number: no, because the sum of its proper divisors is 890 (perfect number is a positive integer that is equal to the sum of its proper divisors).

Number: Prime number: | 633 no | 634 no | 635 no | 636 no | 637 no | 638 no | 639 no | 640 no | 641 yes | 642 no | 643 yes | 644 no | 645 no | 646 no | 647 yes |
---|