165052561 has 2 divisors, whose sum is σ = 165052562. Its totient is φ = 165052560.

The previous prime is 165052549. The next prime is 165052607. The reversal of 165052561 is 165250561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 157351936 + 7700625 = 12544^2 + 2775^2 .

It is a cyclic number.

It is not a de Polignac number, because 165052561 - 2⁹ = 165052049 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (165052501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82526280 + 82526281.

It is an arithmetic number, because the mean of its divisors is an integer number (82526281).

Almost surely, 2^165052561 is an apocalyptic number.

It is an amenable number.

165052561 is a deficient number, since it is larger than the sum of its proper divisors (1).

165052561 is an equidigital number, since it uses as much as digits as its factorization.

165052561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9000, while the sum is 31.

The square root of 165052561 is about 12847.2783499074. The cubic root of 165052561 is about 548.5388888415.

The spelling of 165052561 in words is "one hundred sixty-five million, fifty-two thousand, five hundred sixty-one".