165331321 has 2 divisors, whose sum is σ = 165331322. Its totient is φ = 165331320.

The previous prime is 165331261. The next prime is 165331333. The reversal of 165331321 is 123133561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128595600 + 36735721 = 11340^2 + 6061^2 .

It is a cyclic number.

It is not a de Polignac number, because 165331321 - 2⁷ = 165331193 is a prime.

It is not a weakly prime, because it can be changed into another prime (165338321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82665660 + 82665661.

It is an arithmetic number, because the mean of its divisors is an integer number (82665661).

Almost surely, 2^165331321 is an apocalyptic number.

It is an amenable number.

165331321 is a deficient number, since it is larger than the sum of its proper divisors (1).

165331321 is an equidigital number, since it uses as much as digits as its factorization.

165331321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620, while the sum is 25.

The square root of 165331321 is about 12858.1227634519. The cubic root of 165331321 is about 548.8475272856.

Adding to 165331321 its reverse (123133561), we get a palindrome (288464882).

The spelling of 165331321 in words is "one hundred sixty-five million, three hundred thirty-one thousand, three hundred twenty-one".