138505988 has 12 divisors (see below), whose sum is σ = 242467932. Its totient is φ = 69229440.

The previous prime is 138505979. The next prime is 138505993. The reversal of 138505988 is 889505831.

It can be written as a sum of positive squares in 2 ways, for example, as 14807104 + 123698884 = 3848^2 + 11122^2 .

It is a super-2 number, since 2×138505988² = 38367817423712288, 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, 19568 + ... + 25688.

It is an arithmetic number, because the mean of its divisors is an integer number (20205661).

Almost surely, 2^138505988 is an apocalyptic number.

It is an amenable number.

138505988 is a deficient number, since it is larger than the sum of its proper divisors (103961944).

138505988 is a wasteful number, since it uses less digits than its factorization.

138505988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11782 (or 11780 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 47.

The square root of 138505988 is about 11768.8566989321. The cubic root of 138505988 is about 517.3957414807.

The spelling of 138505988 in words is "one hundred thirty-eight million, five hundred five thousand, nine hundred eighty-eight".