111666171616609 has 2 divisors, whose sum is σ = 111666171616610. Its totient is φ = 111666171616608.

The previous prime is 111666171616607. The next prime is 111666171616729. The reversal of 111666171616609 is 906616171666111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 108276511360000 + 3389660256609 = 10405600^2 + 1841103^2 .

It is a cyclic number.

It is not a de Polignac number, because 111666171616609 - 2¹ = 111666171616607 is a prime.

Together with 111666171616607, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (111666171616607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55833085808304 + 55833085808305.

It is an arithmetic number, because the mean of its divisors is an integer number (55833085808305).

Almost surely, 2^{111666171616609} is an apocalyptic number.

It is an amenable number.

111666171616609 is a deficient number, since it is larger than the sum of its proper divisors (1).

111666171616609 is an equidigital number, since it uses as much as digits as its factorization.

111666171616609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2939328, while the sum is 58.

The spelling of 111666171616609 in words is "one hundred eleven trillion, six hundred sixty-six billion, one hundred seventy-one million, six hundred sixteen thousand, six hundred nine".