638642870 has 32 divisors (see below), whose sum is σ = 1169012736. Its totient is φ = 251154400.

The previous prime is 638642869. The next prime is 638642929. The reversal of 638642870 is 78246836.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 304967 + ... + 307053.

It is an arithmetic number, because the mean of its divisors is an integer number (36531648).

Almost surely, 2^638642870 is an apocalyptic number.

638642870 is a deficient number, since it is larger than the sum of its proper divisors (530369866).

638642870 is a wasteful number, since it uses less digits than its factorization.

638642870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2596.

The product of its (nonzero) digits is 387072, while the sum is 44.

The square root of 638642870 is about 25271.3844100397. The cubic root of 638642870 is about 861.1643099550.

The spelling of 638642870 in words is "six hundred thirty-eight million, six hundred forty-two thousand, eight hundred seventy".