640131626165 has 8 divisors (see below), whose sum is σ = 768200227800. Its totient is φ = 512077116672.

The previous prime is 640131626137. The next prime is 640131626177. The reversal of 640131626165 is 561626131046.

It can be written as a sum of positive squares in 4 ways, for example, as 9506640004 + 630624986161 = 97502^2 + 794119^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640131626165 - 2³⁰ = 639057884341 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3422840 + ... + 3605009.

It is an arithmetic number, because the mean of its divisors is an integer number (96025028475).

Almost surely, 2^640131626165 is an apocalyptic number.

It is an amenable number.

640131626165 is a deficient number, since it is larger than the sum of its proper divisors (128068601635).

640131626165 is a wasteful number, since it uses less digits than its factorization.

640131626165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7046071.

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 640131626165 in words is "six hundred forty billion, one hundred thirty-one million, six hundred twenty-six thousand, one hundred sixty-five".