640842080788 has 54 divisors (see below), whose sum is σ = 1405011617226. Its totient is φ = 253503958176.

The previous prime is 640842080771. The next prime is 640842080803. The reversal of 640842080788 is 887080248046.

It can be written as a sum of positive squares in only one way, i.e., 443659902084 + 197182178704 = 666078^2 + 444052^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 40400803 + ... + 40416661.

Almost surely, 2^640842080788 is an apocalyptic number.

It is an amenable number.

640842080788 is an abundant number, since it is smaller than the sum of its proper divisors (764169536438).

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

640842080788 is an equidigital number, since it uses as much as digits as its factorization.

640842080788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31749 (or 15881 counting only the distinct ones).

The product of its (nonzero) digits is 5505024, while the sum is 55.

The spelling of 640842080788 in words is "six hundred forty billion, eight hundred forty-two million, eighty thousand, seven hundred eighty-eight".