11666155565081 has 2 divisors, whose sum is σ = 11666155565082. Its totient is φ = 11666155565080.

The previous prime is 11666155565033. The next prime is 11666155565147. The reversal of 11666155565081 is 18056555166611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10787841715225 + 878313849856 = 3284485^2 + 937184^2 .

It is a cyclic number.

It is not a de Polignac number, because 11666155565081 - 2⁴² = 7268109053977 is a prime.

It is a super-2 number, since 2×11666155565081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (11666155565021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5833077782540 + 5833077782541.

It is an arithmetic number, because the mean of its divisors is an integer number (5833077782541).

Almost surely, 2^{11666155565081} is an apocalyptic number.

It is an amenable number.

11666155565081 is a deficient number, since it is larger than the sum of its proper divisors (1).

11666155565081 is an equidigital number, since it uses as much as digits as its factorization.

11666155565081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480000, while the sum is 56.

The spelling of 11666155565081 in words is "eleven trillion, six hundred sixty-six billion, one hundred fifty-five million, five hundred sixty-five thousand, eighty-one".