166611616506109 has 2 divisors, whose sum is σ = 166611616506110. Its totient is φ = 166611616506108.

The previous prime is 166611616506067. The next prime is 166611616506161. The reversal of 166611616506109 is 901605616116661.

166611616506109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115194069122500 + 51417547383609 = 10732850^2 + 7170603^2 .

It is a cyclic number.

It is not a de Polignac number, because 166611616506109 - 2²³ = 166611608117501 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166611616506109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166611616506199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83305808253054 + 83305808253055.

It is an arithmetic number, because the mean of its divisors is an integer number (83305808253055).

Almost surely, 2^{166611616506109} is an apocalyptic number.

It is an amenable number.

166611616506109 is a deficient number, since it is larger than the sum of its proper divisors (1).

166611616506109 is an equidigital number, since it uses as much as digits as its factorization.

166611616506109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2099520, while the sum is 55.

The spelling of 166611616506109 in words is "one hundred sixty-six trillion, six hundred eleven billion, six hundred sixteen million, five hundred six thousand, one hundred nine".