166666657 has 4 divisors (see below), whose sum is σ = 176470596. Its totient is φ = 156862720.

The previous prime is 166666649. The next prime is 166666673. The reversal of 166666657 is 756666661.

It is a happy number.

166666657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 756666661 = 79 ⋅9578059.

It can be written as a sum of positive squares in 2 ways, for example, as 120099681 + 46566976 = 10959^2 + 6824^2 .

It is a cyclic number.

It is not a de Polignac number, because 166666657 - 2³ = 166666649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166666657.

It is not an unprimeable number, because it can be changed into a prime (166666627) 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, 4901944 + ... + 4901977.

It is an arithmetic number, because the mean of its divisors is an integer number (44117649).

Almost surely, 2^166666657 is an apocalyptic number.

166666657 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

166666657 is a deficient number, since it is larger than the sum of its proper divisors (9803939).

166666657 is an equidigital number, since it uses as much as digits as its factorization.

166666657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9803938.

The product of its digits is 1632960, while the sum is 49.

The square root of 166666657 is about 12909.9441129697. The cubic root of 166666657 is about 550.3211975096.

The spelling of 166666657 in words is "one hundred sixty-six million, six hundred sixty-six thousand, six hundred fifty-seven".