12665972561 has 8 divisors (see below), whose sum is σ = 13852233984. Its totient is φ = 11485512720.

The previous prime is 12665972551. The next prime is 12665972567. The reversal of 12665972561 is 16527956621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 12665972561 - 2²² = 12661778257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12665972567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1445825 + ... + 1454558.

It is an arithmetic number, because the mean of its divisors is an integer number (1731529248).

Almost surely, 2^12665972561 is an apocalyptic number.

12665972561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12665972561 is a deficient number, since it is larger than the sum of its proper divisors (1186261423).

12665972561 is a wasteful number, since it uses less digits than its factorization.

12665972561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2900791.

The product of its digits is 1360800, while the sum is 50.

The spelling of 12665972561 in words is "twelve billion, six hundred sixty-five million, nine hundred seventy-two thousand, five hundred sixty-one".