165920161 has 9 divisors (see below), whose sum is σ = 182530929. Its totient is φ = 150707700.

The previous prime is 165920147. The next prime is 165920171. The reversal of 165920161 is 161029561.

The square root of 165920161 is 12881.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 165920161 - 2⁷ = 165920033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165920171) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 141106 + ... + 142276.

Almost surely, 2^165920161 is an apocalyptic number.

165920161 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

165920161 is the 12881-st square number.

165920161 is the 6441-st centered octagonal number.

It is an amenable number.

165920161 is a deficient number, since it is larger than the sum of its proper divisors (16610768).

165920161 is an frugal number, since it uses more digits than its factorization.

165920161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2364 (or 1182 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 31.

The cubic root of 165920161 is about 549.4983425752.

The spelling of 165920161 in words is "one hundred sixty-five million, nine hundred twenty thousand, one hundred sixty-one".