12865399664569 has 9 divisors (see below), whose sum is σ = 13030601255973. Its totient is φ = 12702266730972.

The previous prime is 12865399664497. The next prime is 12865399664573. The reversal of 12865399664569 is 96546699356821.

The square root of 12865399664569 is 3586837.

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

It is not a de Polignac number, because 12865399664569 - 2⁹ = 12865399664057 is a prime.

It is a super-2 number, since 2×12865399664569² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (79).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12865399664669) 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, 283337422 + ... + 283382824.

It is an arithmetic number, because the mean of its divisors is an integer number (1447844583997).

Almost surely, 2^{12865399664569} is an apocalyptic number.

12865399664569 is the 3586837-th square number.

12865399664569 is the 1793419-th centered octagonal number.

It is an amenable number.

12865399664569 is a deficient number, since it is larger than the sum of its proper divisors (165201591404).

12865399664569 is an frugal number, since it uses more digits than its factorization.

12865399664569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90964 (or 45482 counting only the distinct ones).

The product of its digits is 4534963200, while the sum is 79.

The spelling of 12865399664569 in words is "twelve trillion, eight hundred sixty-five billion, three hundred ninety-nine million, six hundred sixty-four thousand, five hundred sixty-nine".