644443231556116 has 24 divisors (see below), whose sum is σ = 1142064248635520. Its totient is φ = 318139253033472.

The previous prime is 644443231556107. The next prime is 644443231556209. The reversal of 644443231556116 is 611655132344446.

It is a congruent number.

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, 16449895 + ... + 39490321.

Almost surely, 2^{644443231556116} is an apocalyptic number.

It is an amenable number.

644443231556116 is a deficient number, since it is larger than the sum of its proper divisors (497621017079404).

644443231556116 is a wasteful number, since it uses less digits than its factorization.

644443231556116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23129023 (or 23129021 counting only the distinct ones).

The product of its digits is 24883200, while the sum is 55.

The spelling of 644443231556116 in words is "six hundred forty-four trillion, four hundred forty-three billion, two hundred thirty-one million, five hundred fifty-six thousand, one hundred sixteen".