165633509 has 2 divisors, whose sum is σ = 165633510. Its totient is φ = 165633508.

The previous prime is 165633493. The next prime is 165633521. The reversal of 165633509 is 905336561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163277284 + 2356225 = 12778^2 + 1535^2 .

It is a cyclic number.

It is not a de Polignac number, because 165633509 - 2⁴ = 165633493 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165633599) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82816754 + 82816755.

It is an arithmetic number, because the mean of its divisors is an integer number (82816755).

Almost surely, 2^165633509 is an apocalyptic number.

It is an amenable number.

165633509 is a deficient number, since it is larger than the sum of its proper divisors (1).

165633509 is an equidigital number, since it uses as much as digits as its factorization.

165633509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72900, while the sum is 38.

The square root of 165633509 is about 12869.8682588440. The cubic root of 165633509 is about 549.1817131889.

The spelling of 165633509 in words is "one hundred sixty-five million, six hundred thirty-three thousand, five hundred nine".