640661116 has 24 divisors (see below), whose sum is σ = 1203836256. Its totient is φ = 297239040.

The previous prime is 640661093. The next prime is 640661129. The reversal of 640661116 is 611166046.

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, 61521 + ... + 71176.

It is an arithmetic number, because the mean of its divisors is an integer number (50159844).

Almost surely, 2^640661116 is an apocalyptic number.

It is an amenable number.

640661116 is a deficient number, since it is larger than the sum of its proper divisors (563175140).

640661116 is a wasteful number, since it uses less digits than its factorization.

640661116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132789 (or 132787 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 640661116 is about 25311.2843609328. The cubic root of 640661116 is about 862.0705095719.

The spelling of 640661116 in words is "six hundred forty million, six hundred sixty-one thousand, one hundred sixteen".