72817920 has 432 divisors, whose sum is σ = 307581120. Its totient is φ = 16257024.

The previous prime is 72817903. The next prime is 72817933. The reversal of 72817920 is 2971827.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1693419 + ... + 1693461.

Almost surely, 2^72817920 is an apocalyptic number.

72817920 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72817920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153790560).

72817920 is an abundant number, since it is smaller than the sum of its proper divisors (234763200).

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

72817920 is a wasteful number, since it uses less digits than its factorization.

72817920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 72817920 is about 8533.3416666626. The cubic root of 72817920 is about 417.5861535903.

It can be divided in two parts, 72817 and 920, that added together give a palindrome (73737).

The spelling of 72817920 in words is "seventy-two million, eight hundred seventeen thousand, nine hundred twenty".