165665231 has 4 divisors (see below), whose sum is σ = 165691032. Its totient is φ = 165639432.

The previous prime is 165665207. The next prime is 165665239. The reversal of 165665231 is 132566561.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 165665231 - 2⁶ = 165665167 is a prime.

It is a super-2 number, since 2×165665231² = 54889937524566722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165665191 and 165665200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165665239) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5156 + ... + 18918.

It is an arithmetic number, because the mean of its divisors is an integer number (41422758).

Almost surely, 2^165665231 is an apocalyptic number.

165665231 is a deficient number, since it is larger than the sum of its proper divisors (25801).

165665231 is a wasteful number, since it uses less digits than its factorization.

165665231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25800.

The product of its digits is 32400, while the sum is 35.

The square root of 165665231 is about 12871.1006133897. The cubic root of 165665231 is about 549.2167705683.

The spelling of 165665231 in words is "one hundred sixty-five million, six hundred sixty-five thousand, two hundred thirty-one".