11555555506161 has 4 divisors (see below), whose sum is σ = 15407407341552. Its totient is φ = 7703703670772.

The previous prime is 11555555506133. The next prime is 11555555506177. The reversal of 11555555506161 is 16160555555511.

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 11555555506161 - 2³⁰ = 11554481764337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11555555504161) 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, 1925925917691 + ... + 1925925917696.

It is an arithmetic number, because the mean of its divisors is an integer number (3851851835388).

Almost surely, 2^{11555555506161} is an apocalyptic number.

It is an amenable number.

11555555506161 is a deficient number, since it is larger than the sum of its proper divisors (3851851835391).

11555555506161 is an equidigital number, since it uses as much as digits as its factorization.

11555555506161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3851851835390.

The product of its (nonzero) digits is 2812500, while the sum is 51.

The spelling of 11555555506161 in words is "eleven trillion, five hundred fifty-five billion, five hundred fifty-five million, five hundred six thousand, one hundred sixty-one".