40581 has 12 divisors (see below), whose sum is σ = 61152. Its totient is φ = 26892.

The previous prime is 40577. The next prime is 40583. The reversal of 40581 is 18504.

40581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 40581 - 2² = 40577 is a prime.

It is a super-2 number, since 2×40581² = 3293635122, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 40581.

It is not an unprimeable number, because it can be changed into a prime (40583) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 160 + ... + 326.

It is an arithmetic number, because the mean of its divisors is an integer number (5096).

2⁴⁰⁵⁸¹ is an apocalyptic number.

It is an amenable number.

40581 is a deficient number, since it is larger than the sum of its proper divisors (20571).

40581 is an equidigital number, since it uses as much as digits as its factorization.

40581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 40581 is about 201.4472635704. The cubic root of 40581 is about 34.3643063155.

The spelling of 40581 in words is "forty thousand, five hundred eighty-one".