138459681 has 12 divisors (see below), whose sum is σ = 200222100. Its totient is φ = 92202720.

The previous prime is 138459667. The next prime is 138459683. The reversal of 138459681 is 186954831.

138459681 is a `hidden beast` number, since 138 + 459 + 68 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 51969681 + 86490000 = 7209^2 + 9300^2 .

It is not a de Polignac number, because 138459681 - 2⁵ = 138459649 is a prime.

It is a super-2 number, since 2×138459681² = 38342166525243522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138459683) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 295 + ... + 16643.

It is an arithmetic number, because the mean of its divisors is an integer number (16685175).

Almost surely, 2^138459681 is an apocalyptic number.

It is an amenable number.

138459681 is a deficient number, since it is larger than the sum of its proper divisors (61762419).

138459681 is a wasteful number, since it uses less digits than its factorization.

138459681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17296 (or 17293 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 138459681 is about 11766.8891810878. The cubic root of 138459681 is about 517.3380743826.

The spelling of 138459681 in words is "one hundred thirty-eight million, four hundred fifty-nine thousand, six hundred eighty-one".