166013221 has 4 divisors (see below), whose sum is σ = 181105344. Its totient is φ = 150921100.

The previous prime is 166013179. The next prime is 166013251. The reversal of 166013221 is 122310661.

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 166013221 - 2²¹ = 163916069 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 166013192 and 166013201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166013251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7546045 + ... + 7546066.

It is an arithmetic number, because the mean of its divisors is an integer number (45276336).

Almost surely, 2^166013221 is an apocalyptic number.

166013221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

166013221 is a deficient number, since it is larger than the sum of its proper divisors (15092123).

166013221 is a wasteful number, since it uses less digits than its factorization.

166013221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15092122.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 166013221 is about 12884.6117908147. The cubic root of 166013221 is about 549.6010561496.

Adding to 166013221 its reverse (122310661), we get a palindrome (288323882).

The spelling of 166013221 in words is "one hundred sixty-six million, thirteen thousand, two hundred twenty-one".