72071308521 has 63 divisors (see below), whose sum is σ = 110536116327. Its totient is φ = 46969936560.

The previous prime is 72071308483. The next prime is 72071308523. The reversal of 72071308521 is 12580317027.

The square root of 72071308521 is 268461.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 2343624921 + 69727683600 = 48411^2 + 264060^2 .

It is not a de Polignac number, because 72071308521 - 2⁹ = 72071308009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (72071308523) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 442155186 + ... + 442155348.

It is an arithmetic number, because the mean of its divisors is an integer number (1754541529).

Almost surely, 2^72071308521 is an apocalyptic number.

72071308521 is the 268461-st square number.

72071308521 is the 134231-st centered octagonal number.

It is an amenable number.

72071308521 is a deficient number, since it is larger than the sum of its proper divisors (38464807806).

72071308521 is an frugal number, since it uses more digits than its factorization.

72071308521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 466 (or 227 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

Multiplying 72071308521 by its sum of digits (36), we get a square (2594567106756 = 1610766²).

The spelling of 72071308521 in words is "seventy-two billion, seventy-one million, three hundred eight thousand, five hundred twenty-one".