164166221 has 4 divisors (see below), whose sum is σ = 164215932. Its totient is φ = 164116512.

The previous prime is 164166209. The next prime is 164166227. The reversal of 164166221 is 122661461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 89965225 + 74200996 = 9485^2 + 8614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-164166221 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 (164166227) 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, 19520 + ... + 26633.

It is an arithmetic number, because the mean of its divisors is an integer number (41053983).

Almost surely, 2^164166221 is an apocalyptic number.

It is an amenable number.

164166221 is a deficient number, since it is larger than the sum of its proper divisors (49711).

164166221 is an equidigital number, since it uses as much as digits as its factorization.

164166221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49710.

The product of its digits is 3456, while the sum is 29.

The square root of 164166221 is about 12812.7366709849. The cubic root of 164166221 is about 547.5552327812. Note that the first 3 decimals are identical.

The spelling of 164166221 in words is "one hundred sixty-four million, one hundred sixty-six thousand, two hundred twenty-one".