138888918 has 40 divisors (see below), whose sum is σ = 355676112. Its totient is φ = 39682224.

The previous prime is 138888913. The next prime is 138888931. The reversal of 138888918 is 819888831.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138888913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 60105 + ... + 62372.

Almost surely, 2^138888918 is an apocalyptic number.

138888918 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

138888918 is an abundant number, since it is smaller than the sum of its proper divisors (216787194).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138888918 is a wasteful number, since it uses less digits than its factorization.

138888918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122498 (or 122489 counting only the distinct ones).

The product of its digits is 884736, while the sum is 54.

The square root of 138888918 is about 11785.1142548556. The cubic root of 138888918 is about 517.8721205076.

The spelling of 138888918 in words is "one hundred thirty-eight million, eight hundred eighty-eight thousand, nine hundred eighteen".