644372507 has 2 divisors, whose sum is σ = 644372508. Its totient is φ = 644372506.

The previous prime is 644372497. The next prime is 644372537. The reversal of 644372507 is 705273446.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644372507 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (644372537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322186253 + 322186254.

It is an arithmetic number, because the mean of its divisors is an integer number (322186254).

Almost surely, 2^644372507 is an apocalyptic number.

644372507 is a deficient number, since it is larger than the sum of its proper divisors (1).

644372507 is an equidigital number, since it uses as much as digits as its factorization.

644372507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 141120, while the sum is 38.

The square root of 644372507 is about 25384.4934359542. The cubic root of 644372507 is about 863.7319819648.

The spelling of 644372507 in words is "six hundred forty-four million, three hundred seventy-two thousand, five hundred seven".