165385881 has 20 divisors (see below), whose sum is σ = 247405312. Its totient is φ = 110102328.

The previous prime is 165385879. The next prime is 165385889. The reversal of 165385881 is 188583561.

165385881 is a `hidden beast` number, since 1 + 65 + 3 + 8 + 588 + 1 = 666.

It is not a de Polignac number, because 165385881 - 2¹ = 165385879 is a prime.

It is a super-2 number, since 2×165385881² = 54704979268292322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165385889) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 104760 + ... + 106326.

Almost surely, 2^165385881 is an apocalyptic number.

It is an amenable number.

165385881 is a deficient number, since it is larger than the sum of its proper divisors (82019431).

165385881 is a wasteful number, since it uses less digits than its factorization.

165385881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2882 (or 2873 counting only the distinct ones).

The product of its digits is 230400, while the sum is 45.

The square root of 165385881 is about 12860.2442045243. The cubic root of 165385881 is about 548.9078946084.

The spelling of 165385881 in words is "one hundred sixty-five million, three hundred eighty-five thousand, eight hundred eighty-one".