11666506655561 has 8 divisors (see below), whose sum is σ = 12432761950464. Its totient is φ = 10921836016960.

The previous prime is 11666506655549. The next prime is 11666506655633. The reversal of 11666506655561 is 16555660566611.

It is a happy number.

11666506655561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a de Polignac number, because none of the positive numbers 2^k-11666506655561 is a prime.

It is a super-2 number, since 2×11666506655561² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11666506655561.

It is not an unprimeable number, because it can be changed into a prime (11666506655761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5396162960 + ... + 5396165121.

It is an arithmetic number, because the mean of its divisors is an integer number (1554095243808).

Almost surely, 2^{11666506655561} is an apocalyptic number.

It is an amenable number.

11666506655561 is a deficient number, since it is larger than the sum of its proper divisors (766255294903).

11666506655561 is a wasteful number, since it uses less digits than its factorization.

11666506655561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10792328151.

The product of its (nonzero) digits is 29160000, while the sum is 59.

The spelling of 11666506655561 in words is "eleven trillion, six hundred sixty-six billion, five hundred six million, six hundred fifty-five thousand, five hundred sixty-one".