645002591 has 2 divisors, whose sum is σ = 645002592. Its totient is φ = 645002590.

The previous prime is 645002587. The next prime is 645002599. The reversal of 645002591 is 195200546.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645002591 - 2² = 645002587 is a prime.

It is a super-3 number, since 3×645002591³ (a number of 27 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645002599) 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, 322501295 + 322501296.

It is an arithmetic number, because the mean of its divisors is an integer number (322501296).

Almost surely, 2^645002591 is an apocalyptic number.

645002591 is a deficient number, since it is larger than the sum of its proper divisors (1).

645002591 is an equidigital number, since it uses as much as digits as its factorization.

645002591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 645002591 is about 25396.9012086120. The cubic root of 645002591 is about 864.0134166977.

The spelling of 645002591 in words is "six hundred forty-five million, two thousand, five hundred ninety-one".