12805411921 has 3 divisors (see below), whose sum is σ = 12805525083. Its totient is φ = 12805298760.

The previous prime is 12805411907. The next prime is 12805411967. The reversal of 12805411921 is 12911450821.

The square root of 12805411921 is 113161.

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., 11227733521 + 1577678400 = 105961^2 + 39720^2 .

It is not a de Polignac number, because 12805411921 - 2¹⁷ = 12805280849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12805411981) 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, 56581 + ... + 169741.

It is an arithmetic number, because the mean of its divisors is an integer number (4268508361).

Almost surely, 2^12805411921 is an apocalyptic number.

12805411921 is the 113161-st square number.

12805411921 is the 56581-st centered octagonal number.

It is an amenable number.

12805411921 is a deficient number, since it is larger than the sum of its proper divisors (113162).

12805411921 is an frugal number, since it uses more digits than its factorization.

12805411921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226322 (or 113161 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 34.

The spelling of 12805411921 in words is "twelve billion, eight hundred five million, four hundred eleven thousand, nine hundred twenty-one".