644752638227 has 2 divisors, whose sum is σ = 644752638228. Its totient is φ = 644752638226.

The previous prime is 644752638083. The next prime is 644752638253. The reversal of 644752638227 is 722836257446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644752638227 - 2¹⁰ = 644752637203 is a prime.

It is not a weakly prime, because it can be changed into another prime (644752688227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322376319113 + 322376319114.

It is an arithmetic number, because the mean of its divisors is an integer number (322376319114).

Almost surely, 2^644752638227 is an apocalyptic number.

644752638227 is a deficient number, since it is larger than the sum of its proper divisors (1).

644752638227 is an equidigital number, since it uses as much as digits as its factorization.

644752638227 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27095040, while the sum is 56.

The spelling of 644752638227 in words is "six hundred forty-four billion, seven hundred fifty-two million, six hundred thirty-eight thousand, two hundred twenty-seven".