165621329 has 2 divisors, whose sum is σ = 165621330. Its totient is φ = 165621328.

The previous prime is 165621317. The next prime is 165621371. The reversal of 165621329 is 923126561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111936400 + 53684929 = 10580^2 + 7327^2 .

It is a cyclic number.

It is not a de Polignac number, because 165621329 - 2²⁰ = 164572753 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165621829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82810664 + 82810665.

It is an arithmetic number, because the mean of its divisors is an integer number (82810665).

Almost surely, 2^165621329 is an apocalyptic number.

It is an amenable number.

165621329 is a deficient number, since it is larger than the sum of its proper divisors (1).

165621329 is an equidigital number, since it uses as much as digits as its factorization.

165621329 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 35.

The square root of 165621329 is about 12869.3950518274. The cubic root of 165621329 is about 549.1682513452.

The spelling of 165621329 in words is "one hundred sixty-five million, six hundred twenty-one thousand, three hundred twenty-nine".