640440616360 has 16 divisors (see below), whose sum is σ = 1440991386900. Its totient is φ = 256176246528.

The previous prime is 640440616349. The next prime is 640440616379. The reversal of 640440616360 is 63616044046.

It can be written as a sum of positive squares in 2 ways, for example, as 640323240804 + 117375556 = 800202^2 + 10834^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 16011015409 = 640440616360 / (6 + 4 + 0 + 4 + 4 + 0 + 6 + 1 + 6 + 3 + 6 + 0).

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, 8005507665 + ... + 8005507744.

Almost surely, 2^640440616360 is an apocalyptic number.

It is an amenable number.

640440616360 is an abundant number, since it is smaller than the sum of its proper divisors (800550770540).

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

640440616360 is a wasteful number, since it uses less digits than its factorization.

640440616360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16011015420 (or 16011015416 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 40.

The spelling of 640440616360 in words is "six hundred forty billion, four hundred forty million, six hundred sixteen thousand, three hundred sixty".