181780 has 24 divisors (see below), whose sum is σ = 390600. Its totient is φ = 71040.

The previous prime is 181777. The next prime is 181787. The reversal of 181780 is 87181.

181780 = 103² + 104² + ... + 117².

It can be written as a sum of positive squares in 4 ways, for example, as 7056 + 174724 = 84^2 + 418^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1146 + ... + 1294.

It is an arithmetic number, because the mean of its divisors is an integer number (16275).

2¹⁸¹⁷⁸⁰ is an apocalyptic number.

181780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

181780 is an abundant number, since it is smaller than the sum of its proper divisors (208820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

181780 is a wasteful number, since it uses less digits than its factorization.

181780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 25.

The square root of 181780 is about 426.3566582100. The cubic root of 181780 is about 56.6476676023.

It can be divided in two parts, 181 and 780, that added together give a square (961 = 31²).

The spelling of 181780 in words is "one hundred eighty-one thousand, seven hundred eighty".