166304221 has 4 divisors (see below), whose sum is σ = 166357312. Its totient is φ = 166251132.

The previous prime is 166304213. The next prime is 166304227. The reversal of 166304221 is 122403661.

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 166304221 - 2³ = 166304213 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 (166304227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21531 + ... + 28216.

It is an arithmetic number, because the mean of its divisors is an integer number (41589328).

Almost surely, 2^166304221 is an apocalyptic number.

It is an amenable number.

166304221 is a deficient number, since it is larger than the sum of its proper divisors (53091).

166304221 is an equidigital number, since it uses as much as digits as its factorization.

166304221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53090.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 166304221 is about 12895.8993870145. The cubic root of 166304221 is about 549.9219955490.

Adding to 166304221 its reverse (122403661), we get a palindrome (288707882).

The spelling of 166304221 in words is "one hundred sixty-six million, three hundred four thousand, two hundred twenty-one".