72021591 has 6 divisors (see below), whose sum is σ = 104031200. Its totient is φ = 48014388.

The previous prime is 72021577. The next prime is 72021601. The reversal of 72021591 is 19512027.

72021591 is a `hidden beast` number, since 72 + 0 + 2 + 1 + 591 = 666.

It is not a de Polignac number, because 72021591 - 2⁶ = 72021527 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 (72021991) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4001191 + ... + 4001208.

Almost surely, 2^72021591 is an apocalyptic number.

72021591 is a deficient number, since it is larger than the sum of its proper divisors (32009609).

72021591 is a wasteful number, since it uses less digits than its factorization.

72021591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8002405 (or 8002402 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 72021591 is about 8486.5535407490. The cubic root of 72021591 is about 416.0583447968.

The spelling of 72021591 in words is "seventy-two million, twenty-one thousand, five hundred ninety-one".