644914573670 has 16 divisors (see below), whose sum is σ = 1160892555120. Its totient is φ = 257955535584.

The previous prime is 644914573657. The next prime is 644914573687. The reversal of 644914573670 is 76375419446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1020992 + ... + 1527171.

It is an arithmetic number, because the mean of its divisors is an integer number (72555784695).

Almost surely, 2^644914573670 is an apocalyptic number.

644914573670 is a deficient number, since it is larger than the sum of its proper divisors (515977981450).

644914573670 is a wasteful number, since it uses less digits than its factorization.

644914573670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2573479.

The product of its (nonzero) digits is 15240960, while the sum is 56.

The spelling of 644914573670 in words is "six hundred forty-four billion, nine hundred fourteen million, five hundred seventy-three thousand, six hundred seventy".