72138864 has 80 divisors (see below), whose sum is σ = 217978112. Its totient is φ = 20127744.

The previous prime is 72138791. The next prime is 72138881. The reversal of 72138864 is 46883127.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11952 + ... + 16944.

Almost surely, 2^72138864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72138864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108989056).

72138864 is an abundant number, since it is smaller than the sum of its proper divisors (145839248).

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

72138864 is a wasteful number, since it uses less digits than its factorization.

72138864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5054 (or 5048 counting only the distinct ones).

The product of its digits is 64512, while the sum is 39.

The square root of 72138864 is about 8493.4600723145. The cubic root of 72138864 is about 416.2840454077.

The spelling of 72138864 in words is "seventy-two million, one hundred thirty-eight thousand, eight hundred sixty-four".