138240072 has 24 divisors (see below), whose sum is σ = 374400390. Its totient is φ = 46080000.

The previous prime is 138240061. The next prime is 138240079. The reversal of 138240072 is 270042831.

It can be written as a sum of positive squares in only one way, i.e., 123076836 + 15163236 = 11094^2 + 3894^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×138240072² = 38220635013130368, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138240079) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 959929 + ... + 960072.

Almost surely, 2^138240072 is an apocalyptic number.

138240072 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

138240072 is an abundant number, since it is smaller than the sum of its proper divisors (236160318).

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

138240072 is a wasteful number, since it uses less digits than its factorization.

138240072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920013 (or 1920006 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 138240072 is about 11757.5538272210. The cubic root of 138240072 is about 517.0644153757.

The spelling of 138240072 in words is "one hundred thirty-eight million, two hundred forty thousand, seventy-two".