638973998 has 8 divisors (see below), whose sum is σ = 1032188808. Its totient is φ = 294911064.

The previous prime is 638973967. The next prime is 638974001. The reversal of 638973998 is 899379836.

638973998 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 638973998.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12287936 + ... + 12287987.

It is an arithmetic number, because the mean of its divisors is an integer number (129023601).

Almost surely, 2^638973998 is an apocalyptic number.

638973998 is a deficient number, since it is larger than the sum of its proper divisors (393214810).

638973998 is a wasteful number, since it uses less digits than its factorization.

638973998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24575938.

The product of its digits is 17635968, while the sum is 62.

The square root of 638973998 is about 25277.9350026856. The cubic root of 638973998 is about 861.3131183945.

The spelling of 638973998 in words is "six hundred thirty-eight million, nine hundred seventy-three thousand, nine hundred ninety-eight".