166556213 has 2 divisors, whose sum is σ = 166556214. Its totient is φ = 166556212.

The previous prime is 166556207. The next prime is 166556239. The reversal of 166556213 is 312655661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95609284 + 70946929 = 9778^2 + 8423^2 .

It is a cyclic number.

It is not a de Polignac number, because 166556213 - 2⁴ = 166556197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166556513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83278106 + 83278107.

It is an arithmetic number, because the mean of its divisors is an integer number (83278107).

Almost surely, 2^166556213 is an apocalyptic number.

It is an amenable number.

166556213 is a deficient number, since it is larger than the sum of its proper divisors (1).

166556213 is an equidigital number, since it uses as much as digits as its factorization.

166556213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32400, while the sum is 35.

The square root of 166556213 is about 12905.6659262512. The cubic root of 166556213 is about 550.1996112929.

The spelling of 166556213 in words is "one hundred sixty-six million, five hundred fifty-six thousand, two hundred thirteen".