11111375561 has 16 divisors (see below), whose sum is σ = 13132119168. Its totient is φ = 9268377600.

The previous prime is 11111375521. The next prime is 11111375573. The reversal of 11111375561 is 16557311111.

It is a cyclic number.

It is not a de Polignac number, because 11111375561 - 2⁶ = 11111375497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11111375501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 208760 + ... + 256521.

It is an arithmetic number, because the mean of its divisors is an integer number (820757448).

Almost surely, 2^11111375561 is an apocalyptic number.

11111375561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11111375561 is a deficient number, since it is larger than the sum of its proper divisors (2020743607).

11111375561 is a wasteful number, since it uses less digits than its factorization.

11111375561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465472.

The product of its digits is 3150, while the sum is 32.

Adding to 11111375561 its reverse (16557311111), we get a palindrome (27668686672).

The spelling of 11111375561 in words is "eleven billion, one hundred eleven million, three hundred seventy-five thousand, five hundred sixty-one".