11231561665 has 8 divisors (see below), whose sum is σ = 13479324840. Its totient is φ = 8984282112.

The previous prime is 11231561647. The next prime is 11231561707. The reversal of 11231561665 is 56616513211.

It can be written as a sum of positive squares in 4 ways, for example, as 205721649 + 11025840016 = 14343^2 + 105004^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11231561665 is a prime.

It is a super-2 number, since 2×11231561665² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67680 + ... + 164449.

It is an arithmetic number, because the mean of its divisors is an integer number (1684915605).

Almost surely, 2^11231561665 is an apocalyptic number.

It is an amenable number.

11231561665 is a deficient number, since it is larger than the sum of its proper divisors (2247763175).

11231561665 is an equidigital number, since it uses as much as digits as its factorization.

11231561665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241811.

The product of its digits is 32400, while the sum is 37.

The spelling of 11231561665 in words is "eleven billion, two hundred thirty-one million, five hundred sixty-one thousand, six hundred sixty-five".