640973398 has 24 divisors (see below), whose sum is σ = 1095913800. Its totient is φ = 280260864.

The previous prime is 640973387. The next prime is 640973419. The reversal of 640973398 is 893379046.

640973398 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 43483 + ... + 56326.

It is an arithmetic number, because the mean of its divisors is an integer number (45663075).

Almost surely, 2^640973398 is an apocalyptic number.

640973398 is a deficient number, since it is larger than the sum of its proper divisors (454940402).

640973398 is a wasteful number, since it uses less digits than its factorization.

640973398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99856 (or 99843 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 49.

The square root of 640973398 is about 25317.4524389797. The cubic root of 640973398 is about 862.2105552046.

The spelling of 640973398 in words is "six hundred forty million, nine hundred seventy-three thousand, three hundred ninety-eight".