165285881 has 4 divisors (see below), whose sum is σ = 165896064. Its totient is φ = 164675700.

The previous prime is 165285871. The next prime is 165285899. The reversal of 165285881 is 188582561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 188582561 = 1783 ⋅105767.

It is a cyclic number.

It is not a de Polignac number, because 165285881 - 2⁶ = 165285817 is a prime.

It is a super-2 number, since 2×165285881² = 54638844915892322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165285871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 304685 + ... + 305226.

It is an arithmetic number, because the mean of its divisors is an integer number (41474016).

Almost surely, 2^165285881 is an apocalyptic number.

It is an amenable number.

165285881 is a deficient number, since it is larger than the sum of its proper divisors (610183).

165285881 is an equidigital number, since it uses as much as digits as its factorization.

165285881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610182.

The product of its digits is 153600, while the sum is 44.

The square root of 165285881 is about 12856.3556655842. The cubic root of 165285881 is about 548.7972405509.

The spelling of 165285881 in words is "one hundred sixty-five million, two hundred eighty-five thousand, eight hundred eighty-one".