138618081 has 64 divisors (see below), whose sum is σ = 246988800. Its totient is φ = 75168000.

The previous prime is 138618071. The next prime is 138618083. The reversal of 138618081 is 180816831.

138618081 is a `hidden beast` number, since 1 + 38 + 618 + 0 + 8 + 1 = 666.

It is not a de Polignac number, because 138618081 - 2⁵ = 138618049 is a prime.

It is a super-2 number, since 2×138618081² = 38429944760245122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138618083) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 345481 + ... + 345881.

It is an arithmetic number, because the mean of its divisors is an integer number (3859200).

Almost surely, 2^138618081 is an apocalyptic number.

It is an amenable number.

138618081 is a deficient number, since it is larger than the sum of its proper divisors (108370719).

138618081 is a wasteful number, since it uses less digits than its factorization.

138618081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 507 (or 501 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 138618081 is about 11773.6180080721. The cubic root of 138618081 is about 517.5352800984.

The spelling of 138618081 in words is "one hundred thirty-eight million, six hundred eighteen thousand, eighty-one".