181540 has 24 divisors (see below), whose sum is σ = 395640. Its totient is φ = 69888.

The previous prime is 181537. The next prime is 181549. The reversal of 181540 is 45181.

It can be written as a sum of positive squares in 4 ways, for example, as 64 + 181476 = 8^2 + 426^2 .

It is not an unprimeable number, because it can be changed into a prime (181549) 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, 424 + ... + 736.

It is an arithmetic number, because the mean of its divisors is an integer number (16485).

2¹⁸¹⁵⁴⁰ is an apocalyptic number.

181540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (197820).

181540 is an abundant number, since it is smaller than the sum of its proper divisors (214100).

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

181540 is a wasteful number, since it uses less digits than its factorization.

181540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351 (or 349 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 181540 is about 426.0751107493. The cubic root of 181540 is about 56.6227264136.

The spelling of 181540 in words is "one hundred eighty-one thousand, five hundred forty".