165810959 has 4 divisors (see below), whose sum is σ = 168082416. Its totient is φ = 163539504.

The previous prime is 165810943. The next prime is 165810961. The reversal of 165810959 is 959018561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 959018561 = 11113 ⋅86297.

It is a cyclic number.

It is not a de Polignac number, because 165810959 - 2⁴ = 165810943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165810989) 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 in 3 ways as a sum of consecutive naturals, for example, 1135619 + ... + 1135764.

It is an arithmetic number, because the mean of its divisors is an integer number (42020604).

Almost surely, 2^165810959 is an apocalyptic number.

165810959 is a deficient number, since it is larger than the sum of its proper divisors (2271457).

165810959 is an equidigital number, since it uses as much as digits as its factorization.

165810959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2271456.

The product of its (nonzero) digits is 97200, while the sum is 44.

The square root of 165810959 is about 12876.7604233363. The cubic root of 165810959 is about 549.3777635227.

The spelling of 165810959 in words is "one hundred sixty-five million, eight hundred ten thousand, nine hundred fifty-nine".