181845 has 20 divisors (see below), whose sum is σ = 326700. Its totient is φ = 96768.

The previous prime is 181837. The next prime is 181871. The reversal of 181845 is 548181.

181845 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 88209 + 93636 = 297^2 + 306^2 .

It is not a de Polignac number, because 181845 - 2³ = 181837 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 181 + ... + 629.

It is an arithmetic number, because the mean of its divisors is an integer number (16335).

2¹⁸¹⁸⁴⁵ is an apocalyptic number.

181845 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

181845 is the 270-th heptagonal number.

It is an amenable number.

181845 is a deficient number, since it is larger than the sum of its proper divisors (144855).

181845 is an equidigital number, since it uses as much as digits as its factorization.

181845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466 (or 457 counting only the distinct ones).

The product of its digits is 1280, while the sum is 27.

The square root of 181845 is about 426.4328786574. The cubic root of 181845 is about 56.6544187293.

It can be divided in two parts, 1818 and 45, that multiplied together give a triangular number (81810 = T₄₀₄).

The spelling of 181845 in words is "one hundred eighty-one thousand, eight hundred forty-five".