165042221 has 2 divisors, whose sum is σ = 165042222. Its totient is φ = 165042220.

The previous prime is 165042211. The next prime is 165042253. The reversal of 165042221 is 122240561.

It is a happy number.

165042221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159112996 + 5929225 = 12614^2 + 2435^2 .

It is a cyclic number.

It is not a de Polignac number, because 165042221 - 2¹⁰ = 165041197 is a prime.

It is a super-2 number, since 2×165042221² = 54477869425225682, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165042211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82521110 + 82521111.

It is an arithmetic number, because the mean of its divisors is an integer number (82521111).

Almost surely, 2^165042221 is an apocalyptic number.

It is an amenable number.

165042221 is a deficient number, since it is larger than the sum of its proper divisors (1).

165042221 is an equidigital number, since it uses as much as digits as its factorization.

165042221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 165042221 is about 12846.8759237411. The cubic root of 165042221 is about 548.5274338833.

Adding to 165042221 its reverse (122240561), we get a palindrome (287282782).

The spelling of 165042221 in words is "one hundred sixty-five million, forty-two thousand, two hundred twenty-one".