165622921 has 2 divisors, whose sum is σ = 165622922. Its totient is φ = 165622920.

The previous prime is 165622909. The next prime is 165622927. The reversal of 165622921 is 129226561.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125440000 + 40182921 = 11200^2 + 6339^2 .

It is a cyclic number.

It is not a de Polignac number, because 165622921 - 2¹⁵ = 165590153 is a prime.

It is not a weakly prime, because it can be changed into another prime (165622927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82811460 + 82811461.

It is an arithmetic number, because the mean of its divisors is an integer number (82811461).

Almost surely, 2^165622921 is an apocalyptic number.

It is an amenable number.

165622921 is a deficient number, since it is larger than the sum of its proper divisors (1).

165622921 is an equidigital number, since it uses as much as digits as its factorization.

165622921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 34.

The square root of 165622921 is about 12869.4569038480. The cubic root of 165622921 is about 549.1700109275.

The spelling of 165622921 in words is "one hundred sixty-five million, six hundred twenty-two thousand, nine hundred twenty-one".