138888881 has 8 divisors (see below), whose sum is σ = 145052160. Its totient is φ = 132736032.

The previous prime is 138888857. The next prime is 138888907. The reversal of 138888881 is 188888831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 138888881 - 2²² = 134694577 is a prime.

It is a super-2 number, since 2×138888881² = 38580242530864322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138888481) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38741 + ... + 42173.

It is an arithmetic number, because the mean of its divisors is an integer number (18131520).

Almost surely, 2^138888881 is an apocalyptic number.

It is an amenable number.

138888881 is a deficient number, since it is larger than the sum of its proper divisors (6163279).

138888881 is a wasteful number, since it uses less digits than its factorization.

138888881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5215.

The product of its digits is 786432, while the sum is 53.

The square root of 138888881 is about 11785.1126850786. The cubic root of 138888881 is about 517.8720745206.

The spelling of 138888881 in words is "one hundred thirty-eight million, eight hundred eighty-eight thousand, eight hundred eighty-one".