166430221 has 4 divisors (see below), whose sum is σ = 176220252. Its totient is φ = 156640192.

The previous prime is 166430191. The next prime is 166430233. The reversal of 166430221 is 122034661.

166430221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122034661 = 7 ⋅17433523.

It can be written as a sum of positive squares in 2 ways, for example, as 90060100 + 76370121 = 9490^2 + 8739^2 .

It is a cyclic number.

It is not a de Polignac number, because 166430221 - 2⁹ = 166429709 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 (166430281) 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, 4894990 + ... + 4895023.

It is an arithmetic number, because the mean of its divisors is an integer number (44055063).

Almost surely, 2^166430221 is an apocalyptic number.

It is an amenable number.

166430221 is a deficient number, since it is larger than the sum of its proper divisors (9790031).

166430221 is an equidigital number, since it uses as much as digits as its factorization.

166430221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9790030.

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

The square root of 166430221 is about 12900.7837358821. The cubic root of 166430221 is about 550.0608428559.

Adding to 166430221 its reverse (122034661), we get a palindrome (288464882).

The spelling of 166430221 in words is "one hundred sixty-six million, four hundred thirty thousand, two hundred twenty-one".