640012536 has 128 divisors (see below), whose sum is σ = 1895270400. Its totient is φ = 199647360.

The previous prime is 640012517. The next prime is 640012543. The reversal of 640012536 is 635210046.

640012536 is a `hidden beast` number, since 6 + 400 + 1 + 253 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 232126 + ... + 234866.

It is an arithmetic number, because the mean of its divisors is an integer number (14806800).

Almost surely, 2^640012536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640012536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (947635200).

640012536 is an abundant number, since it is smaller than the sum of its proper divisors (1255257864).

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

640012536 is a wasteful number, since it uses less digits than its factorization.

640012536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2826 (or 2816 counting only the distinct ones).

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

The square root of 640012536 is about 25298.4690445884. The cubic root of 640012536 is about 861.7795026413.

The spelling of 640012536 in words is "six hundred forty million, twelve thousand, five hundred thirty-six".