72558021 has 16 divisors (see below), whose sum is σ = 98207744. Its totient is φ = 47646144.

The previous prime is 72558001. The next prime is 72558043. The reversal of 72558021 is 12085527.

It is not a de Polignac number, because 72558021 - 2⁶ = 72557957 is a prime.

It is a super-2 number, since 2×72558021² = 10529332822872882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72558021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72558001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 59211 + ... + 60423.

It is an arithmetic number, because the mean of its divisors is an integer number (6137984).

Almost surely, 2^72558021 is an apocalyptic number.

It is an amenable number.

72558021 is a deficient number, since it is larger than the sum of its proper divisors (25649723).

72558021 is a wasteful number, since it uses less digits than its factorization.

72558021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1500.

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 72558021 is about 8518.0996120027. The cubic root of 72558021 is about 417.0887503822.

The spelling of 72558021 in words is "seventy-two million, five hundred fifty-eight thousand, twenty-one".