640717021512 has 64 divisors (see below), whose sum is σ = 1780447032000. Its totient is φ = 213491037312.

The previous prime is 640717021493. The next prime is 640717021517. The reversal of 640717021512 is 215120717046.

640717021512 is a `hidden beast` number, since 6 + 4 + 0 + 71 + 70 + 2 + 1 + 512 = 666.

It is a super-2 number, since 2×640717021512² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (640717021517) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 5439 + ... + 1132017.

It is an arithmetic number, because the mean of its divisors is an integer number (27819484875).

Almost surely, 2^640717021512 is an apocalyptic number.

It is an amenable number.

640717021512 is an abundant number, since it is smaller than the sum of its proper divisors (1139730010488).

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

640717021512 is a wasteful number, since it uses less digits than its factorization.

640717021512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1129227 (or 1129217 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

Adding to 640717021512 its reverse (215120717046), we get a palindrome (855837738558).

The spelling of 640717021512 in words is "six hundred forty billion, seven hundred seventeen million, twenty-one thousand, five hundred twelve".