165861081 has 8 divisors (see below), whose sum is σ = 245720160. Its totient is φ = 110574036.

The previous prime is 165861079. The next prime is 165861097. The reversal of 165861081 is 180168561.

It is not a de Polignac number, because 165861081 - 2¹ = 165861079 is a prime.

It is a super-2 number, since 2×165861081² = 55019796380977122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (165861001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3071475 + ... + 3071528.

It is an arithmetic number, because the mean of its divisors is an integer number (30715020).

Almost surely, 2^165861081 is an apocalyptic number.

It is an amenable number.

165861081 is a deficient number, since it is larger than the sum of its proper divisors (79859079).

165861081 is an equidigital number, since it uses as much as digits as its factorization.

165861081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6143012 (or 6143006 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 165861081 is about 12878.7064956074. The cubic root of 165861081 is about 549.4331139819.

The spelling of 165861081 in words is "one hundred sixty-five million, eight hundred sixty-one thousand, eighty-one".