11666645661 has 16 divisors (see below), whose sum is σ = 17184476160. Its totient is φ = 6981190320.

The previous prime is 11666645651. The next prime is 11666645681. The reversal of 11666645661 is 16654666611.

It is not a de Polignac number, because 11666645661 - 2⁷ = 11666645533 is a prime.

It is a super-2 number, since 2×11666645661² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 11666645661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11666645611) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 2234955 + ... + 2240168.

It is an arithmetic number, because the mean of its divisors is an integer number (1074029760).

Almost surely, 2^11666645661 is an apocalyptic number.

11666645661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11666645661 is a deficient number, since it is larger than the sum of its proper divisors (5517830499).

11666645661 is a wasteful number, since it uses less digits than its factorization.

11666645661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4475216.

The product of its digits is 933120, while the sum is 48.

The spelling of 11666645661 in words is "eleven billion, six hundred sixty-six million, six hundred forty-five thousand, six hundred sixty-one".