165353921 has 2 divisors, whose sum is σ = 165353922. Its totient is φ = 165353920.

The previous prime is 165353897. The next prime is 165353933. The reversal of 165353921 is 129353561.

165353921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 131423296 + 33930625 = 11464^2 + 5825^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165353921 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (165353971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82676960 + 82676961.

It is an arithmetic number, because the mean of its divisors is an integer number (82676961).

Almost surely, 2^165353921 is an apocalyptic number.

It is an amenable number.

165353921 is a deficient number, since it is larger than the sum of its proper divisors (1).

165353921 is an equidigital number, since it uses as much as digits as its factorization.

165353921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24300, while the sum is 35.

The square root of 165353921 is about 12859.0015553308. The cubic root of 165353921 is about 548.8725344226.

The spelling of 165353921 in words is "one hundred sixty-five million, three hundred fifty-three thousand, nine hundred twenty-one".