6531321366025 has 81 divisors (see below), whose sum is σ = 8614717142997. Its totient is φ = 4911745238400.

The previous prime is 6531321366013. The next prime is 6531321366091. The reversal of 6531321366025 is 5206631231356.

The square root of 6531321366025 is 2555645.

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

It can be written as a sum of positive squares in 4 ways, for example, as 3669174729081 + 2862146636944 = 1915509^2 + 1691788^2 .

It is not a de Polignac number, because 6531321366025 - 2¹³ = 6531321357833 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 20866841269 + ... + 20866841581.

Almost surely, 2^{6531321366025} is an apocalyptic number.

6531321366025 is the 2555645-th square number.

6531321366025 is the 1277823-rd centered octagonal number.

It is an amenable number.

6531321366025 is a deficient number, since it is larger than the sum of its proper divisors (2083395776972).

6531321366025 is an frugal number, since it uses more digits than its factorization.

6531321366025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 824 (or 412 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 43.

The spelling of 6531321366025 in words is "six trillion, five hundred thirty-one billion, three hundred twenty-one million, three hundred sixty-six thousand, twenty-five".