138815866 has 16 divisors (see below), whose sum is σ = 246176640. Its totient is φ = 57440880.

The previous prime is 138815857. The next prime is 138815891. The reversal of 138815866 is 668518831.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 170550 + ... + 171361.

It is an arithmetic number, because the mean of its divisors is an integer number (15386040).

Almost surely, 2^138815866 is an apocalyptic number.

138815866 is a deficient number, since it is larger than the sum of its proper divisors (107360774).

138815866 is a wasteful number, since it uses less digits than its factorization.

138815866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341949.

The product of its digits is 276480, while the sum is 46.

The square root of 138815866 is about 11782.0145136560. The cubic root of 138815866 is about 517.7813087773.

The spelling of 138815866 in words is "one hundred thirty-eight million, eight hundred fifteen thousand, eight hundred sixty-six".