12921564817 has 16 divisors (see below), whose sum is σ = 15086518272. Its totient is φ = 10836516240.

The previous prime is 12921564787. The next prime is 12921564839. The reversal of 12921564817 is 71846512921.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12921564817 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12921564857) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2057392 + ... + 2063662.

It is an arithmetic number, because the mean of its divisors is an integer number (942907392).

Almost surely, 2^12921564817 is an apocalyptic number.

It is an amenable number.

12921564817 is a deficient number, since it is larger than the sum of its proper divisors (2164953455).

12921564817 is an equidigital number, since it uses as much as digits as its factorization.

12921564817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12588.

The product of its digits is 241920, while the sum is 46.

The spelling of 12921564817 in words is "twelve billion, nine hundred twenty-one million, five hundred sixty-four thousand, eight hundred seventeen".