644550465185 has 16 divisors (see below), whose sum is σ = 843952798080. Its totient is φ = 468665283840.

The previous prime is 644550465179. The next prime is 644550465239. The reversal of 644550465185 is 581564055446.

It is not a de Polignac number, because 644550465185 - 2²² = 644546270881 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 969512 + ... + 1493001.

It is an arithmetic number, because the mean of its divisors is an integer number (52747049880).

Almost surely, 2^644550465185 is an apocalyptic number.

It is an amenable number.

644550465185 is a deficient number, since it is larger than the sum of its proper divisors (199402332895).

644550465185 is a wasteful number, since it uses less digits than its factorization.

644550465185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2467288.

The product of its (nonzero) digits is 11520000, while the sum is 53.

The spelling of 644550465185 in words is "six hundred forty-four billion, five hundred fifty million, four hundred sixty-five thousand, one hundred eighty-five".