165444121 has 2 divisors, whose sum is σ = 165444122. Its totient is φ = 165444120.

The previous prime is 165444113. The next prime is 165444137. The reversal of 165444121 is 121444561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 157854096 + 7590025 = 12564^2 + 2755^2 .

It is a cyclic number.

It is not a de Polignac number, because 165444121 - 2³ = 165444113 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165444121.

It is not a weakly prime, because it can be changed into another prime (165444821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82722060 + 82722061.

It is an arithmetic number, because the mean of its divisors is an integer number (82722061).

Almost surely, 2^165444121 is an apocalyptic number.

It is an amenable number.

165444121 is a deficient number, since it is larger than the sum of its proper divisors (1).

165444121 is an equidigital number, since it uses as much as digits as its factorization.

165444121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 28.

The square root of 165444121 is about 12862.5083479079. The cubic root of 165444121 is about 548.9723189793.

Adding to 165444121 its reverse (121444561), we get a palindrome (286888682).

The spelling of 165444121 in words is "one hundred sixty-five million, four hundred forty-four thousand, one hundred twenty-one".