640491552 has 72 divisors (see below), whose sum is σ = 1844519040. Its totient is φ = 210787200.

The previous prime is 640491461. The next prime is 640491581. The reversal of 640491552 is 255194046.

640491552 is a `hidden beast` number, since 64 + 0 + 49 + 1 + 552 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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

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, 8677 + ... + 36827.

It is an arithmetic number, because the mean of its divisors is an integer number (25618320).

Almost surely, 2^640491552 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 640491552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (922259520).

640491552 is an abundant number, since it is smaller than the sum of its proper divisors (1204027488).

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

640491552 is a wasteful number, since it uses less digits than its factorization.

640491552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28246 (or 28235 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 640491552 is about 25307.9345660605. The cubic root of 640491552 is about 861.9944480274.

The spelling of 640491552 in words is "six hundred forty million, four hundred ninety-one thousand, five hundred fifty-two".