11506605665 has 4 divisors (see below), whose sum is σ = 13807926804. Its totient is φ = 9205284528.

The previous prime is 11506605647. The next prime is 11506605673. The reversal of 11506605665 is 56650660511.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4662021841 + 6844583824 = 68279^2 + 82732^2 .

It is a cyclic number.

It is not a de Polignac number, because 11506605665 - 2¹² = 11506601569 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1150660562 + ... + 1150660571.

It is an arithmetic number, because the mean of its divisors is an integer number (3451981701).

Almost surely, 2^11506605665 is an apocalyptic number.

It is an amenable number.

11506605665 is a deficient number, since it is larger than the sum of its proper divisors (2301321139).

11506605665 is an equidigital number, since it uses as much as digits as its factorization.

11506605665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2301321138.

The product of its (nonzero) digits is 162000, while the sum is 41.

The spelling of 11506605665 in words is "eleven billion, five hundred six million, six hundred five thousand, six hundred sixty-five".