12126562561 has 4 divisors (see below), whose sum is σ = 12127295232. Its totient is φ = 12125829892.

The previous prime is 12126562559. The next prime is 12126562571. The reversal of 12126562561 is 16526562121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 12126562561 - 2¹ = 12126562559 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12126562561.

It is not an unprimeable number, because it can be changed into a prime (12126562531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 340921 + ... + 374806.

It is an arithmetic number, because the mean of its divisors is an integer number (3031823808).

Almost surely, 2^12126562561 is an apocalyptic number.

It is an amenable number.

12126562561 is a deficient number, since it is larger than the sum of its proper divisors (732671).

12126562561 is an equidigital number, since it uses as much as digits as its factorization.

12126562561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732670.

The product of its digits is 43200, while the sum is 37.

The spelling of 12126562561 in words is "twelve billion, one hundred twenty-six million, five hundred sixty-two thousand, five hundred sixty-one".