33581 has 2 divisors, whose sum is σ = 33582. Its totient is φ = 33580.

The previous prime is 33577. The next prime is 33587. The reversal of 33581 is 18533.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17956 + 15625 = 134^2 + 125^2 .

It is a cyclic number.

It is not a de Polignac number, because 33581 - 2² = 33577 is a prime.

It is a super-2 number, since 2×33581² = 2255367122, which contains 22 as substring.

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 33581.

It is not a weakly prime, because it can be changed into another prime (33587) 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 as a sum of consecutive naturals, namely, 16790 + 16791.

It is an arithmetic number, because the mean of its divisors is an integer number (16791).

2³³⁵⁸¹ is an apocalyptic number.

It is an amenable number.

33581 is a deficient number, since it is larger than the sum of its proper divisors (1).

33581 is an equidigital number, since it uses as much as digits as its factorization.

33581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 20.

The square root of 33581 is about 183.2511937205. The cubic root of 33581 is about 32.2624894038.

The spelling of 33581 in words is "thirty-three thousand, five hundred eighty-one".