166538717 has 4 divisors (see below), whose sum is σ = 166638780. Its totient is φ = 166438656.

The previous prime is 166538683. The next prime is 166538731. The reversal of 166538717 is 717835661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 717835661 = 149 ⋅4817689.

It can be written as a sum of positive squares in 2 ways, for example, as 125910841 + 40627876 = 11221^2 + 6374^2 .

It is a cyclic number.

It is not a de Polignac number, because 166538717 - 2²⁰ = 165490141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166538737) 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, 47492 + ... + 50877.

It is an arithmetic number, because the mean of its divisors is an integer number (41659695).

Almost surely, 2^166538717 is an apocalyptic number.

It is an amenable number.

166538717 is a deficient number, since it is larger than the sum of its proper divisors (100063).

166538717 is an equidigital number, since it uses as much as digits as its factorization.

166538717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100062.

The product of its digits is 211680, while the sum is 44.

The square root of 166538717 is about 12904.9880666353. The cubic root of 166538717 is about 550.1803452660.

The spelling of 166538717 in words is "one hundred sixty-six million, five hundred thirty-eight thousand, seven hundred seventeen".