166570221 has 4 divisors (see below), whose sum is σ = 222093632. Its totient is φ = 111046812.

The previous prime is 166570213. The next prime is 166570231. The reversal of 166570221 is 122075661.

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 not a de Polignac number, because 166570221 - 2³ = 166570213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166570211) 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, 27761701 + ... + 27761706.

It is an arithmetic number, because the mean of its divisors is an integer number (55523408).

Almost surely, 2^166570221 is an apocalyptic number.

It is an amenable number.

166570221 is a deficient number, since it is larger than the sum of its proper divisors (55523411).

166570221 is an equidigital number, since it uses as much as digits as its factorization.

166570221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55523410.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 166570221 is about 12906.2086222097. The cubic root of 166570221 is about 550.2150354751.

The spelling of 166570221 in words is "one hundred sixty-six million, five hundred seventy thousand, two hundred twenty-one".