166681582909 has 2 divisors, whose sum is σ = 166681582910. Its totient is φ = 166681582908.

The previous prime is 166681582867. The next prime is 166681582913. The reversal of 166681582909 is 909285186661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147746446884 + 18935136025 = 384378^2 + 137605^2 .

It is a cyclic number.

It is not a de Polignac number, because 166681582909 - 2²¹ = 166679485757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166681582919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83340791454 + 83340791455.

It is an arithmetic number, because the mean of its divisors is an integer number (83340791455).

Almost surely, 2^166681582909 is an apocalyptic number.

It is an amenable number.

166681582909 is a deficient number, since it is larger than the sum of its proper divisors (1).

166681582909 is an equidigital number, since it uses as much as digits as its factorization.

166681582909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11197440, while the sum is 61.

The spelling of 166681582909 in words is "one hundred sixty-six billion, six hundred eighty-one million, five hundred eighty-two thousand, nine hundred nine".