640382784 has 84 divisors (see below), whose sum is σ = 1722327264. Its totient is φ = 209991936.

The previous prime is 640382773. The next prime is 640382833. The reversal of 640382784 is 487283046.

It is a super-2 number, since 2×640382784² = 820180220087181312, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 861517 + ... + 862259.

It is an arithmetic number, because the mean of its divisors is an integer number (20503896).

Almost surely, 2^640382784 is an apocalyptic number.

640382784 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640382784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (861163632).

640382784 is an abundant number, since it is smaller than the sum of its proper divisors (1081944480).

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

640382784 is an equidigital number, since it uses as much as digits as its factorization.

640382784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 892 (or 815 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 42.

The square root of 640382784 is about 25305.7855835380. The cubic root of 640382784 is about 861.9456507562.

The spelling of 640382784 in words is "six hundred forty million, three hundred eighty-two thousand, seven hundred eighty-four".