72421128 has 80 divisors (see below), whose sum is σ = 218475180. Its totient is φ = 22280832.

The previous prime is 72421109. The next prime is 72421163. The reversal of 72421128 is 82112427.

It can be written as a sum of positive squares in 2 ways, for example, as 71876484 + 544644 = 8478^2 + 738^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4126 + ... + 12722.

Almost surely, 2^72421128 is an apocalyptic number.

72421128 is a gapful number since it is divisible by the number (78) 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 72421128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109237590).

72421128 is an abundant number, since it is smaller than the sum of its proper divisors (146054052).

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

72421128 is a wasteful number, since it uses less digits than its factorization.

72421128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8628 (or 8615 counting only the distinct ones).

The product of its digits is 1792, while the sum is 27.

The square root of 72421128 is about 8510.0603993156. The cubic root of 72421128 is about 416.8262823847.

The spelling of 72421128 in words is "seventy-two million, four hundred twenty-one thousand, one hundred twenty-eight".