644259265523 has 2 divisors, whose sum is σ = 644259265524. Its totient is φ = 644259265522.

The previous prime is 644259265519. The next prime is 644259265537. The reversal of 644259265523 is 325562952446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644259265523 - 2² = 644259265519 is a prime.

It is not a weakly prime, because it can be changed into another prime (644259265513) 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, 322129632761 + 322129632762.

It is an arithmetic number, because the mean of its divisors is an integer number (322129632762).

Almost surely, 2^644259265523 is an apocalyptic number.

644259265523 is a deficient number, since it is larger than the sum of its proper divisors (1).

644259265523 is an equidigital number, since it uses as much as digits as its factorization.

644259265523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552000, while the sum is 53.

The spelling of 644259265523 in words is "six hundred forty-four billion, two hundred fifty-nine million, two hundred sixty-five thousand, five hundred twenty-three".