165819959 has 2 divisors, whose sum is σ = 165819960. Its totient is φ = 165819958.

The previous prime is 165819947. The next prime is 165819967. The reversal of 165819959 is 959918561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165819959 - 2⁴ = 165819943 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165819959.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165819919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82909979 + 82909980.

It is an arithmetic number, because the mean of its divisors is an integer number (82909980).

Almost surely, 2^165819959 is an apocalyptic number.

165819959 is a deficient number, since it is larger than the sum of its proper divisors (1).

165819959 is an equidigital number, since it uses as much as digits as its factorization.

165819959 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 874800, while the sum is 53.

The square root of 165819959 is about 12877.1098853741. The cubic root of 165819959 is about 549.3877031761.

The spelling of 165819959 in words is "one hundred sixty-five million, eight hundred nineteen thousand, nine hundred fifty-nine".