165773561 has 2 divisors, whose sum is σ = 165773562. Its totient is φ = 165773560.

The previous prime is 165773549. The next prime is 165773593. The reversal of 165773561 is 165377561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162690025 + 3083536 = 12755^2 + 1756^2 .

It is a cyclic number.

It is not a de Polignac number, because 165773561 - 2¹⁴ = 165757177 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165773261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82886780 + 82886781.

It is an arithmetic number, because the mean of its divisors is an integer number (82886781).

Almost surely, 2^165773561 is an apocalyptic number.

It is an amenable number.

165773561 is a deficient number, since it is larger than the sum of its proper divisors (1).

165773561 is an equidigital number, since it uses as much as digits as its factorization.

165773561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 132300, while the sum is 41.

The square root of 165773561 is about 12875.3081904862. The cubic root of 165773561 is about 549.3364570964.

The spelling of 165773561 in words is "one hundred sixty-five million, seven hundred seventy-three thousand, five hundred sixty-one".