138817881 has 12 divisors (see below), whose sum is σ = 207941552. Its totient is φ = 92545092.

The previous prime is 138817873. The next prime is 138817897. The reversal of 138817881 is 188718831.

It is not a de Polignac number, because 138817881 - 2³ = 138817873 is a prime.

It is a super-2 number, since 2×138817881² = 38540808170660322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138817831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 285391 + ... + 285876.

Almost surely, 2^138817881 is an apocalyptic number.

It is an amenable number.

138817881 is a deficient number, since it is larger than the sum of its proper divisors (69123671).

138817881 is an frugal number, since it uses more digits than its factorization.

138817881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 571282 (or 571270 counting only the distinct ones).

The product of its digits is 86016, while the sum is 45.

The square root of 138817881 is about 11782.1000250380. The cubic root of 138817881 is about 517.7838140728.

The spelling of 138817881 in words is "one hundred thirty-eight million, eight hundred seventeen thousand, eight hundred eighty-one".