644404060136236 has 24 divisors (see below), whose sum is σ = 1158397063433120. Its totient is φ = 313436649347712.

The previous prime is 644404060136173. The next prime is 644404060136237. The reversal of 644404060136236 is 632631060404446.

It is a self number, because there is not a number n which added to its sum of digits gives 644404060136236.

It is not an unprimeable number, because it can be changed into a prime (644404060136237) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 396531825 + ... + 398153608.

Almost surely, 2^{644404060136236} is an apocalyptic number.

It is an amenable number.

644404060136236 is a deficient number, since it is larger than the sum of its proper divisors (513993003296884).

644404060136236 is a wasteful number, since it uses less digits than its factorization.

644404060136236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794690953 (or 794690951 counting only the distinct ones).

The product of its (nonzero) digits is 5971968, while the sum is 49.

The spelling of 644404060136236 in words is "six hundred forty-four trillion, four hundred four billion, sixty million, one hundred thirty-six thousand, two hundred thirty-six".