166668396889 has 4 divisors (see below), whose sum is σ = 166687473060. Its totient is φ = 166649320720.

The previous prime is 166668396887. The next prime is 166668396893. The reversal of 166668396889 is 988693866661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 988693866661 = 397489 ⋅2487349.

It can be written as a sum of positive squares in 2 ways, for example, as 38618931289 + 128049465600 = 196517^2 + 357840^2 .

It is a cyclic number.

It is not a de Polignac number, because 166668396889 - 2¹ = 166668396887 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166668396887) 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, 9524974 + ... + 9542455.

It is an arithmetic number, because the mean of its divisors is an integer number (41671868265).

Almost surely, 2^166668396889 is an apocalyptic number.

It is an amenable number.

166668396889 is a deficient number, since it is larger than the sum of its proper divisors (19076171).

166668396889 is an equidigital number, since it uses as much as digits as its factorization.

166668396889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19076170.

The product of its digits is 967458816, while the sum is 76.

The spelling of 166668396889 in words is "one hundred sixty-six billion, six hundred sixty-eight million, three hundred ninety-six thousand, eight hundred eighty-nine".