640173444 has 24 divisors (see below), whose sum is σ = 1558683840. Its totient is φ = 204113184.

The previous prime is 640173431. The next prime is 640173449. The reversal of 640173444 is 444371046.

It is a super-2 number, since 2×640173444² = 819644076805642272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640173449) 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, 1159459 + ... + 1160010.

It is an arithmetic number, because the mean of its divisors is an integer number (64945160).

Almost surely, 2^640173444 is an apocalyptic number.

It is an amenable number.

640173444 is an abundant number, since it is smaller than the sum of its proper divisors (918510396).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640173444 is a wasteful number, since it uses less digits than its factorization.

640173444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2319499 (or 2319497 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 33.

The square root of 640173444 is about 25301.6490371675. The cubic root of 640173444 is about 861.8517176835.

The spelling of 640173444 in words is "six hundred forty million, one hundred seventy-three thousand, four hundred forty-four".