166326221 has 4 divisors (see below), whose sum is σ = 166861344. Its totient is φ = 165791100.

The previous prime is 166326163. The next prime is 166326229. The reversal of 166326221 is 122623661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 166326221 - 2⁶ = 166326157 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 (166326229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267095 + ... + 267716.

It is an arithmetic number, because the mean of its divisors is an integer number (41715336).

Almost surely, 2^166326221 is an apocalyptic number.

It is an amenable number.

166326221 is a deficient number, since it is larger than the sum of its proper divisors (535123).

166326221 is an equidigital number, since it uses as much as digits as its factorization.

166326221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535122.

The product of its digits is 5184, while the sum is 29.

The square root of 166326221 is about 12896.7523431289. The cubic root of 166326221 is about 549.9462437819.

Adding to 166326221 its reverse (122623661), we get a palindrome (288949882).

The spelling of 166326221 in words is "one hundred sixty-six million, three hundred twenty-six thousand, two hundred twenty-one".