138815660 has 12 divisors (see below), whose sum is σ = 291512928. Its totient is φ = 55526256.

The previous prime is 138815657. The next prime is 138815671. The reversal of 138815660 is 66518831.

It is a happy number.

It is a super-2 number, since 2×138815660² = 38539574922471200, which contains 22 as substring.

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, 3470372 + ... + 3470411.

It is an arithmetic number, because the mean of its divisors is an integer number (24292744).

Almost surely, 2^138815660 is an apocalyptic number.

138815660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138815660 is an abundant number, since it is smaller than the sum of its proper divisors (152697268).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138815660 is a wasteful number, since it uses less digits than its factorization.

138815660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6940792 (or 6940790 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 38.

The square root of 138815660 is about 11782.0057715145. The cubic root of 138815660 is about 517.7810526514.

The spelling of 138815660 in words is "one hundred thirty-eight million, eight hundred fifteen thousand, six hundred sixty".