644754564136 has 32 divisors (see below), whose sum is σ = 1274027040000. Its totient is φ = 305053623936.

The previous prime is 644754564121. The next prime is 644754564143. The reversal of 644754564136 is 631465457446.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 2344536 + ... + 2605063.

It is an arithmetic number, because the mean of its divisors is an integer number (39813345000).

Almost surely, 2^644754564136 is an apocalyptic number.

It is an amenable number.

644754564136 is a deficient number, since it is larger than the sum of its proper divisors (629272475864).

644754564136 is a wasteful number, since it uses less digits than its factorization.

644754564136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4950481 (or 4950477 counting only the distinct ones).

The product of its digits is 29030400, while the sum is 55.

The spelling of 644754564136 in words is "six hundred forty-four billion, seven hundred fifty-four million, five hundred sixty-four thousand, one hundred thirty-six".