166265221 has 8 divisors (see below), whose sum is σ = 168548600. Its totient is φ = 163995840.

The previous prime is 166265201. The next prime is 166265227. The reversal of 166265221 is 122562661.

It can be written as a sum of positive squares in 4 ways, for example, as 121308196 + 44957025 = 11014^2 + 6705^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 166265221 - 2⁵ = 166265189 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 (166265227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21631 + ... + 28291.

It is an arithmetic number, because the mean of its divisors is an integer number (21068575).

Almost surely, 2^166265221 is an apocalyptic number.

It is an amenable number.

166265221 is a deficient number, since it is larger than the sum of its proper divisors (2283379).

166265221 is a wasteful number, since it uses less digits than its factorization.

166265221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6999.

The product of its digits is 8640, while the sum is 31.

The square root of 166265221 is about 12894.3871897815. The cubic root of 166265221 is about 549.8790047890.

The spelling of 166265221 in words is "one hundred sixty-six million, two hundred sixty-five thousand, two hundred twenty-one".