640898808 has 32 divisors (see below), whose sum is σ = 1747906560. Its totient is φ = 194211680.

The previous prime is 640898801. The next prime is 640898809. The reversal of 640898808 is 808898046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640898801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1213560 + ... + 1214087.

It is an arithmetic number, because the mean of its divisors is an integer number (54622080).

Almost surely, 2^640898808 is an apocalyptic number.

It is an amenable number.

640898808 is an abundant number, since it is smaller than the sum of its proper divisors (1107007752).

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

640898808 is a wasteful number, since it uses less digits than its factorization.

640898808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2427667 (or 2427663 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 51.

The square root of 640898808 is about 25315.9793016190. The cubic root of 640898808 is about 862.1771087930.

The spelling of 640898808 in words is "six hundred forty million, eight hundred ninety-eight thousand, eight hundred eight".