72731421 has 12 divisors (see below), whose sum is σ = 120064672. Its totient is φ = 41560776.

The previous prime is 72731387. The next prime is 72731441. The reversal of 72731421 is 12413727.

It is a happy number.

It is not a de Polignac number, because 72731421 - 2⁶ = 72731357 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72731441) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 577171 + ... + 577296.

Almost surely, 2^72731421 is an apocalyptic number.

It is an amenable number.

72731421 is a deficient number, since it is larger than the sum of its proper divisors (47333251).

72731421 is a wasteful number, since it uses less digits than its factorization.

72731421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1154480 (or 1154477 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 72731421 is about 8528.2718648036. The cubic root of 72731421 is about 417.4207405686.

The spelling of 72731421 in words is "seventy-two million, seven hundred thirty-one thousand, four hundred twenty-one".