111666171616661 has 4 divisors (see below), whose sum is σ = 112654367825772. Its totient is φ = 110677975407552.

The previous prime is 111666171616609. The next prime is 111666171616729. The reversal of 111666171616661 is 166616171666111.

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 8438153522500 + 103228018094161 = 2904850^2 + 10160119^2 .

It is a cyclic number.

It is not a de Polignac number, because 111666171616661 - 2³⁴ = 111648991747477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 111666171616597 and 111666171616606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111666171616561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 494098104386 + ... + 494098104611.

It is an arithmetic number, because the mean of its divisors is an integer number (28163591956443).

Almost surely, 2^{111666171616661} is an apocalyptic number.

It is an amenable number.

111666171616661 is a deficient number, since it is larger than the sum of its proper divisors (988196209111).

111666171616661 is an equidigital number, since it uses as much as digits as its factorization.

111666171616661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 988196209110.

The product of its digits is 1959552, while the sum is 56.

The spelling of 111666171616661 in words is "one hundred eleven trillion, six hundred sixty-six billion, one hundred seventy-one million, six hundred sixteen thousand, six hundred sixty-one".