72720172 has 48 divisors (see below), whose sum is σ = 151244800. Its totient is φ = 29937600.

The previous prime is 72720161. The next prime is 72720199. The reversal of 72720172 is 27102727.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 72720172.

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, 172522 + ... + 172942.

Almost surely, 2^72720172 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 72720172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75622400).

72720172 is an abundant number, since it is smaller than the sum of its proper divisors (78524628).

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

72720172 is a wasteful number, since it uses less digits than its factorization.

72720172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 2744, while the sum is 28.

The square root of 72720172 is about 8527.6123270233. The cubic root of 72720172 is about 417.3992193428.

Adding to 72720172 its reverse (27102727), we get a palindrome (99822899).

The spelling of 72720172 in words is "seventy-two million, seven hundred twenty thousand, one hundred seventy-two".