165506213 has 2 divisors, whose sum is σ = 165506214. Its totient is φ = 165506212.

The previous prime is 165506197. The next prime is 165506249. The reversal of 165506213 is 312605561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 114211969 + 51294244 = 10687^2 + 7162^2 .

It is a cyclic number.

It is not a de Polignac number, because 165506213 - 2⁴ = 165506197 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165506293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82753106 + 82753107.

It is an arithmetic number, because the mean of its divisors is an integer number (82753107).

Almost surely, 2^165506213 is an apocalyptic number.

It is an amenable number.

165506213 is a deficient number, since it is larger than the sum of its proper divisors (1).

165506213 is an equidigital number, since it uses as much as digits as its factorization.

165506213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 165506213 is about 12864.9218031048. The cubic root of 165506213 is about 549.0409877350.

The spelling of 165506213 in words is "one hundred sixty-five million, five hundred six thousand, two hundred thirteen".