640456632 has 96 divisors (see below), whose sum is σ = 1816214400. Its totient is φ = 211421664.

The previous prime is 640456631. The next prime is 640456637. The reversal of 640456632 is 236654046.

640456632 is a `hidden beast` number, since 64 + 0 + 4 + 566 + 32 = 666.

640456632 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640456631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 206469 + ... + 209547.

It is an arithmetic number, because the mean of its divisors is an integer number (18918900).

Almost surely, 2^640456632 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 640456632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (908107200).

640456632 is an abundant number, since it is smaller than the sum of its proper divisors (1175757768).

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

640456632 is a wasteful number, since it uses less digits than its factorization.

640456632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3207 (or 3191 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 640456632 is about 25307.2446544463. The cubic root of 640456632 is about 861.9787822506.

It can be divided in two parts, 6404 and 56632, that added together give a palindrome (63036).

The spelling of 640456632 in words is "six hundred forty million, four hundred fifty-six thousand, six hundred thirty-two".