10991177765 has 4 divisors (see below), whose sum is σ = 13189413324. Its totient is φ = 8792942208.

The previous prime is 10991177713. The next prime is 10991177777. The reversal of 10991177765 is 56777119901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56777119901 = 97 ⋅585331133.

It can be written as a sum of positive squares in 2 ways, for example, as 4222660324 + 6768517441 = 64982^2 + 82271^2 .

It is a cyclic number.

It is not a de Polignac number, because 10991177765 - 2¹⁴ = 10991161381 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1099117772 + ... + 1099117781.

It is an arithmetic number, because the mean of its divisors is an integer number (3297353331).

Almost surely, 2^10991177765 is an apocalyptic number.

It is an amenable number.

10991177765 is a deficient number, since it is larger than the sum of its proper divisors (2198235559).

10991177765 is an equidigital number, since it uses as much as digits as its factorization.

10991177765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2198235558.

The product of its (nonzero) digits is 833490, while the sum is 53.

The spelling of 10991177765 in words is "ten billion, nine hundred ninety-one million, one hundred seventy-seven thousand, seven hundred sixty-five".