11165937561 has 45 divisors (see below), whose sum is σ = 17053176261. Its totient is φ = 7281016776.

The previous prime is 11165937539. The next prime is 11165937611. The reversal of 11165937561 is 16573956111.

The square root of 11165937561 is 105669.

It is a perfect power (a square), and thus also a powerful number.

11165937561 is a `hidden beast` number, since 1 + 1 + 1 + 6 + 59 + 37 + 561 = 666.

It is not a de Polignac number, because 11165937561 - 2⁵ = 11165937529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11165937521) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 56110140 + ... + 56110338.

Almost surely, 2^11165937561 is an apocalyptic number.

11165937561 is the 105669-th square number.

11165937561 is the 52835-th centered octagonal number.

It is an amenable number.

11165937561 is a deficient number, since it is larger than the sum of its proper divisors (5887238700).

11165937561 is an frugal number, since it uses more digits than its factorization.

11165937561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528 (or 261 counting only the distinct ones).

The product of its digits is 170100, while the sum is 45.

The spelling of 11165937561 in words is "eleven billion, one hundred sixty-five million, nine hundred thirty-seven thousand, five hundred sixty-one".