640616944 has 20 divisors (see below), whose sum is σ = 1354031640. Its totient is φ = 291189440.

The previous prime is 640616903. The next prime is 640616959. The reversal of 640616944 is 449616046.

It is a junction number, because it is equal to n+sod(n) for n = 640616897 and 640616906.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1819759 + ... + 1820110.

It is an arithmetic number, because the mean of its divisors is an integer number (67701582).

Almost surely, 2^640616944 is an apocalyptic number.

It is an amenable number.

640616944 is an abundant number, since it is smaller than the sum of its proper divisors (713414696).

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

640616944 is a wasteful number, since it uses less digits than its factorization.

640616944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3639888 (or 3639882 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 40.

The square root of 640616944 is about 25310.4117706528. The cubic root of 640616944 is about 862.0506965731.

The spelling of 640616944 in words is "six hundred forty million, six hundred sixteen thousand, nine hundred forty-four".