645900659 has 2 divisors, whose sum is σ = 645900660. Its totient is φ = 645900658.

The previous prime is 645900653. The next prime is 645900667. The reversal of 645900659 is 956009546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645900659 - 2⁴ = 645900643 is a prime.

It is a super-2 number, since 2×645900659² = 834375322593268562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (645900653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322950329 + 322950330.

It is an arithmetic number, because the mean of its divisors is an integer number (322950330).

Almost surely, 2^645900659 is an apocalyptic number.

645900659 is a deficient number, since it is larger than the sum of its proper divisors (1).

645900659 is an equidigital number, since it uses as much as digits as its factorization.

645900659 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 291600, while the sum is 44.

The square root of 645900659 is about 25414.5757194567. The cubic root of 645900659 is about 864.4142331506.

The spelling of 645900659 in words is "six hundred forty-five million, nine hundred thousand, six hundred fifty-nine".