644510893931 has 2 divisors, whose sum is σ = 644510893932. Its totient is φ = 644510893930.

The previous prime is 644510893841. The next prime is 644510893937. The reversal of 644510893931 is 139398015446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644510893931 - 2¹⁴ = 644510877547 is a prime.

It is a super-2 number, since 2×644510893931² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (644510893937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322255446965 + 322255446966.

It is an arithmetic number, because the mean of its divisors is an integer number (322255446966).

Almost surely, 2^644510893931 is an apocalyptic number.

644510893931 is a deficient number, since it is larger than the sum of its proper divisors (1).

644510893931 is an equidigital number, since it uses as much as digits as its factorization.

644510893931 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2799360, while the sum is 53.

The spelling of 644510893931 in words is "six hundred forty-four billion, five hundred ten million, eight hundred ninety-three thousand, nine hundred thirty-one".