72185421 has 32 divisors (see below), whose sum is σ = 120646656. Its totient is φ = 37296000.

The previous prime is 72185371. The next prime is 72185423. The reversal of 72185421 is 12458127.

It is not a de Polignac number, because 72185421 - 2¹⁴ = 72169037 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72185423) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48001 + ... + 49481.

It is an arithmetic number, because the mean of its divisors is an integer number (3770208).

Almost surely, 2^72185421 is an apocalyptic number.

It is an amenable number.

72185421 is a deficient number, since it is larger than the sum of its proper divisors (48461235).

72185421 is a wasteful number, since it uses less digits than its factorization.

72185421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1713.

The product of its digits is 4480, while the sum is 30.

The square root of 72185421 is about 8496.2003860549. The cubic root of 72185421 is about 416.3735799866.

The spelling of 72185421 in words is "seventy-two million, one hundred eighty-five thousand, four hundred twenty-one".