165681559 has 2 divisors, whose sum is σ = 165681560. Its totient is φ = 165681558.

The previous prime is 165681547. The next prime is 165681563. The reversal of 165681559 is 955186561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165681559 - 2⁷ = 165681431 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165681589) 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, 82840779 + 82840780.

It is an arithmetic number, because the mean of its divisors is an integer number (82840780).

Almost surely, 2^165681559 is an apocalyptic number.

165681559 is a deficient number, since it is larger than the sum of its proper divisors (1).

165681559 is an equidigital number, since it uses as much as digits as its factorization.

165681559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 324000, while the sum is 46.

The square root of 165681559 is about 12871.7348869529. The cubic root of 165681559 is about 549.2348136156.

The spelling of 165681559 in words is "one hundred sixty-five million, six hundred eighty-one thousand, five hundred fifty-nine".