72730421 has 4 divisors (see below), whose sum is σ = 73963200. Its totient is φ = 71497644.

The previous prime is 72730409. The next prime is 72730457. The reversal of 72730421 is 12403727.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72730421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72730921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 616301 + ... + 616418.

It is an arithmetic number, because the mean of its divisors is an integer number (18490800).

Almost surely, 2^72730421 is an apocalyptic number.

It is an amenable number.

72730421 is a deficient number, since it is larger than the sum of its proper divisors (1232779).

72730421 is a wasteful number, since it uses less digits than its factorization.

72730421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1232778.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 72730421 is about 8528.2132360771. The cubic root of 72730421 is about 417.4188274906.

The spelling of 72730421 in words is "seventy-two million, seven hundred thirty thousand, four hundred twenty-one".