640645555231 has 32 divisors (see below), whose sum is σ = 707248281600. Its totient is φ = 575483482080.

The previous prime is 640645555229. The next prime is 640645555267. The reversal of 640645555231 is 132555546046.

640645555231 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 640645555231 - 2¹ = 640645555229 is a prime.

It is a super-2 number, since 2×640645555231² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640645555631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 431992216 + ... + 431993698.

It is an arithmetic number, because the mean of its divisors is an integer number (22101508800).

Almost surely, 2^640645555231 is an apocalyptic number.

640645555231 is a deficient number, since it is larger than the sum of its proper divisors (66602726369).

640645555231 is a wasteful number, since it uses less digits than its factorization.

640645555231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2779.

The product of its (nonzero) digits is 2160000, while the sum is 46.

The spelling of 640645555231 in words is "six hundred forty billion, six hundred forty-five million, five hundred fifty-five thousand, two hundred thirty-one".