165309121 has 2 divisors, whose sum is σ = 165309122. Its totient is φ = 165309120.

The previous prime is 165309113. The next prime is 165309181. The reversal of 165309121 is 121903561.

165309121 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., 159668496 + 5640625 = 12636^2 + 2375^2 .

It is a cyclic number.

It is not a de Polignac number, because 165309121 - 2³ = 165309113 is a prime.

It is equal to p_9255232 and since 165309121 and 9255232 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165309121.

It is not a weakly prime, because it can be changed into another prime (165309181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82654560 + 82654561.

It is an arithmetic number, because the mean of its divisors is an integer number (82654561).

Almost surely, 2^165309121 is an apocalyptic number.

It is an amenable number.

165309121 is a deficient number, since it is larger than the sum of its proper divisors (1).

165309121 is an equidigital number, since it uses as much as digits as its factorization.

165309121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 165309121 is about 12857.2594669315. The cubic root of 165309121 is about 548.8229605339.

It can be divided in two parts, 16530 and 9121, that added together give a triangular number (25651 = T₂₂₆).

The spelling of 165309121 in words is "one hundred sixty-five million, three hundred nine thousand, one hundred twenty-one".