640534131 has 6 divisors (see below), whose sum is σ = 925215980. Its totient is φ = 427022748.

The previous prime is 640534127. The next prime is 640534171. The reversal of 640534131 is 131435046.

640534131 is a `hidden beast` number, since 640 + 5 + 3 + 4 + 13 + 1 = 666.

It is not a de Polignac number, because 640534131 - 2² = 640534127 is a prime.

It is a super-2 number, since 2×640534131² = 820567945951850322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640534095 and 640534104.

It is not an unprimeable number, because it can be changed into a prime (640534171) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35585221 + ... + 35585238.

Almost surely, 2^640534131 is an apocalyptic number.

640534131 is a deficient number, since it is larger than the sum of its proper divisors (284681849).

640534131 is a wasteful number, since it uses less digits than its factorization.

640534131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71170465 (or 71170462 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 640534131 is about 25308.7757704714. The cubic root of 640534131 is about 862.0135490071.

Adding to 640534131 its reverse (131435046), we get a palindrome (771969177).

The spelling of 640534131 in words is "six hundred forty million, five hundred thirty-four thousand, one hundred thirty-one".