12158604112561 has 3 divisors (see below), whose sum is σ = 12158607599481. Its totient is φ = 12158600625642.

The previous prime is 12158604112549. The next prime is 12158604112601. The reversal of 12158604112561 is 16521140685121.

The square root of 12158604112561 is 3486919.

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 is not a de Polignac number, because 12158604112561 - 2¹³ = 12158604104369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12158601112561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1743460 + ... + 5230378.

It is an arithmetic number, because the mean of its divisors is an integer number (4052869199827).

Almost surely, 2^{12158604112561} is an apocalyptic number.

12158604112561 is the 3486919-th square number.

12158604112561 is the 1743460-th centered octagonal number.

It is an amenable number.

12158604112561 is a deficient number, since it is larger than the sum of its proper divisors (3486920).

12158604112561 is an frugal number, since it uses more digits than its factorization.

12158604112561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6973838 (or 3486919 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 43.

Adding to 12158604112561 its reverse (16521140685121), we get a palindrome (28679744797682).

The spelling of 12158604112561 in words is "twelve trillion, one hundred fifty-eight billion, six hundred four million, one hundred twelve thousand, five hundred sixty-one".