640381898 has 24 divisors (see below), whose sum is σ = 1043100000. Its totient is φ = 294722064.

The previous prime is 640381883. The next prime is 640381901. The reversal of 640381898 is 898183046.

It is a Curzon 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, 125603 + ... + 130601.

It is an arithmetic number, because the mean of its divisors is an integer number (43462500).

Almost surely, 2^640381898 is an apocalyptic number.

640381898 is a deficient number, since it is larger than the sum of its proper divisors (402718102).

640381898 is a wasteful number, since it uses less digits than its factorization.

640381898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5406 (or 5393 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 47.

The square root of 640381898 is about 25305.7680776538. The cubic root of 640381898 is about 861.9452532418.

The spelling of 640381898 in words is "six hundred forty million, three hundred eighty-one thousand, eight hundred ninety-eight".