665626642210640 has 120 divisors (see below), whose sum is σ = 1705220227956840. Its totient is φ = 241454250639360.

The previous prime is 665626642210631. The next prime is 665626642210681. The reversal of 665626642210640 is 46012246626566.

It can be written as a sum of positive squares in 4 ways, for example, as 20499560190736 + 645127082019904 = 4527644^2 + 25399352^2 .

It is a super-2 number, since 2×665626642210640² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80103329 + ... + 88021568.

It is an arithmetic number, because the mean of its divisors is an integer number (14210168566307).

Almost surely, 2^{665626642210640} is an apocalyptic number.

It is an amenable number.

665626642210640 is an abundant number, since it is smaller than the sum of its proper divisors (1039593585746200).

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

665626642210640 is a wasteful number, since it uses less digits than its factorization.

665626642210640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168125341 (or 168125324 counting only the distinct ones).

The product of its (nonzero) digits is 29859840, while the sum is 56.

The spelling of 665626642210640 in words is "six hundred sixty-five trillion, six hundred twenty-six billion, six hundred forty-two million, two hundred ten thousand, six hundred forty".