166557565 has 4 divisors (see below), whose sum is σ = 199869084. Its totient is φ = 133246048.

The previous prime is 166557563. The next prime is 166557569. The reversal of 166557565 is 565755661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 84437721 + 82119844 = 9189^2 + 9062^2 .

It is a cyclic number.

It is not a de Polignac number, because 166557565 - 2¹ = 166557563 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 (166557563) 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, 16655752 + ... + 16655761.

It is an arithmetic number, because the mean of its divisors is an integer number (49967271).

Almost surely, 2^166557565 is an apocalyptic number.

It is an amenable number.

166557565 is a deficient number, since it is larger than the sum of its proper divisors (33311519).

166557565 is an equidigital number, since it uses as much as digits as its factorization.

166557565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33311518.

The product of its digits is 945000, while the sum is 46.

The square root of 166557565 is about 12905.7183062393. The cubic root of 166557565 is about 550.2011000153.

The spelling of 166557565 in words is "one hundred sixty-six million, five hundred fifty-seven thousand, five hundred sixty-five".