77583974521 has 9 divisors (see below), whose sum is σ = 78937965583. Its totient is φ = 76252836640.

The previous prime is 77583974473. The next prime is 77583974557. The reversal of 77583974521 is 12547938577.

The square root of 77583974521 is 278539.

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., 41938534521 + 35645440000 = 204789^2 + 188800^2 .

It is not a de Polignac number, because 77583974521 - 2²⁷ = 77449756793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77583974591) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 16431441 + ... + 16436161.

Almost surely, 2^77583974521 is an apocalyptic number.

77583974521 is the 278539-th square number.

77583974521 is the 139270-th centered octagonal number.

It is an amenable number.

77583974521 is a deficient number, since it is larger than the sum of its proper divisors (1353991062).

77583974521 is an frugal number, since it uses more digits than its factorization.

77583974521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9560 (or 4780 counting only the distinct ones).

The product of its digits is 14817600, while the sum is 58.

The spelling of 77583974521 in words is "seventy-seven billion, five hundred eighty-three million, nine hundred seventy-four thousand, five hundred twenty-one".