166564709 has 4 divisors (see below), whose sum is σ = 169295340. Its totient is φ = 163834080.

The previous prime is 166564687. The next prime is 166564733. The reversal of 166564709 is 907465661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 907465661 = 17 ⋅53380333.

It can be written as a sum of positive squares in 2 ways, for example, as 56776225 + 109788484 = 7535^2 + 10478^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166564709 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 166564709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166564789) 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, 1365224 + ... + 1365345.

It is an arithmetic number, because the mean of its divisors is an integer number (42323835).

Almost surely, 2^166564709 is an apocalyptic number.

It is an amenable number.

166564709 is a deficient number, since it is larger than the sum of its proper divisors (2730631).

166564709 is an equidigital number, since it uses as much as digits as its factorization.

166564709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2730630.

The product of its (nonzero) digits is 272160, while the sum is 44.

The square root of 166564709 is about 12905.9950798069. The cubic root of 166564709 is about 550.2089663256.

The spelling of 166564709 in words is "one hundred sixty-six million, five hundred sixty-four thousand, seven hundred nine".