640884558 has 32 divisors (see below), whose sum is σ = 1340179200. Its totient is φ = 204316728.

The previous prime is 640884551. The next prime is 640884589. The reversal of 640884558 is 855488046.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640884551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68613 + ... + 77391.

It is an arithmetic number, because the mean of its divisors is an integer number (41880600).

Almost surely, 2^640884558 is an apocalyptic number.

640884558 is an abundant number, since it is smaller than the sum of its proper divisors (699294642).

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

640884558 is an equidigital number, since it uses as much as digits as its factorization.

640884558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8853 (or 8807 counting only the distinct ones).

The product of its (nonzero) digits is 1228800, while the sum is 48.

The square root of 640884558 is about 25315.6978572584. The cubic root of 640884558 is about 862.1707187490.

The spelling of 640884558 in words is "six hundred forty million, eight hundred eighty-four thousand, five hundred fifty-eight".