7831383968521 has 3 divisors (see below), whose sum is σ = 7831386766983. Its totient is φ = 7831381170060.

The previous prime is 7831383968501. The next prime is 7831383968531. The reversal of 7831383968521 is 1258693831387.

The square root of 7831383968521 is 2798461.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 178304352121 + 7653079616400 = 422261^2 + 2766420^2 .

It is a de Polignac number, because none of the positive numbers 2^k-7831383968521 is a prime.

It is a super-2 number, since 2×7831383968521² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7831383968501) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1399231 + ... + 4197691.

It is an arithmetic number, because the mean of its divisors is an integer number (2610462255661).

Almost surely, 2^{7831383968521} is an apocalyptic number.

7831383968521 is the 2798461-st square number.

7831383968521 is the 1399231-st centered octagonal number.

It is an amenable number.

7831383968521 is a deficient number, since it is larger than the sum of its proper divisors (2798462).

7831383968521 is an frugal number, since it uses more digits than its factorization.

7831383968521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5596922 (or 2798461 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 64.

Multiplying 7831383968521 by its sum of digits (64), we get a square (501208573985344 = 22387688²).

The spelling of 7831383968521 in words is "seven trillion, eight hundred thirty-one billion, three hundred eighty-three million, nine hundred sixty-eight thousand, five hundred twenty-one".