644238978024959 has 2 divisors, whose sum is σ = 644238978024960. Its totient is φ = 644238978024958.

The previous prime is 644238978024911. The next prime is 644238978024979. The reversal of 644238978024959 is 959420879832446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644238978024959 - 2⁸ = 644238978024703 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644238978024979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322119489012479 + 322119489012480.

It is an arithmetic number, because the mean of its divisors is an integer number (322119489012480).

Almost surely, 2^{644238978024959} is an apocalyptic number.

644238978024959 is a deficient number, since it is larger than the sum of its proper divisors (1).

644238978024959 is an equidigital number, since it uses as much as digits as its factorization.

644238978024959 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7524679680, while the sum is 80.

The spelling of 644238978024959 in words is "six hundred forty-four trillion, two hundred thirty-eight billion, nine hundred seventy-eight million, twenty-four thousand, nine hundred fifty-nine".