165523121 has 2 divisors, whose sum is σ = 165523122. Its totient is φ = 165523120.

The previous prime is 165523103. The next prime is 165523159. The reversal of 165523121 is 121325561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 108972721 + 56550400 = 10439^2 + 7520^2 .

It is a cyclic number.

It is not a de Polignac number, because 165523121 - 2²⁶ = 98414257 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165523181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82761560 + 82761561.

It is an arithmetic number, because the mean of its divisors is an integer number (82761561).

Almost surely, 2^165523121 is an apocalyptic number.

It is an amenable number.

165523121 is a deficient number, since it is larger than the sum of its proper divisors (1).

165523121 is an equidigital number, since it uses as much as digits as its factorization.

165523121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 26.

The square root of 165523121 is about 12865.5789220695. The cubic root of 165523121 is about 549.0596836473.

Adding to 165523121 its reverse (121325561), we get a palindrome (286848682).

The spelling of 165523121 in words is "one hundred sixty-five million, five hundred twenty-three thousand, one hundred twenty-one".