166705685 has 4 divisors (see below), whose sum is σ = 200046828. Its totient is φ = 133364544.

The previous prime is 166705667. The next prime is 166705691. The reversal of 166705685 is 586507661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 586507661 = 857 ⋅684373.

It can be written as a sum of positive squares in 2 ways, for example, as 46430596 + 120275089 = 6814^2 + 10967^2 .

It is a cyclic number.

It is not a de Polignac number, because 166705685 - 2¹⁰ = 166704661 is a prime.

It is a super-2 number, since 2×166705685² = 55581570822638450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16670564 + ... + 16670573.

It is an arithmetic number, because the mean of its divisors is an integer number (50011707).

Almost surely, 2^166705685 is an apocalyptic number.

It is an amenable number.

166705685 is a deficient number, since it is larger than the sum of its proper divisors (33341143).

166705685 is an equidigital number, since it uses as much as digits as its factorization.

166705685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33341142.

The product of its (nonzero) digits is 302400, while the sum is 44.

The square root of 166705685 is about 12911.4555724752. The cubic root of 166705685 is about 550.3641500309.

The spelling of 166705685 in words is "one hundred sixty-six million, seven hundred five thousand, six hundred eighty-five".