33561 has 16 divisors (see below), whose sum is σ = 54720. Its totient is φ = 20160.

The previous prime is 33547. The next prime is 33563. The reversal of 33561 is 16533.

It is not a de Polignac number, because 33561 - 2⁵ = 33529 is a prime.

It is a super-2 number, since 2×33561² = 2252681442, which contains 22 as substring.

33561 is a lucky number.

It is a plaindrome in base 13.

It is a nialpdrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (33563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 241 + ... + 353.

It is an arithmetic number, because the mean of its divisors is an integer number (3420).

2³³⁵⁶¹ is an apocalyptic number.

It is an amenable number.

33561 is a deficient number, since it is larger than the sum of its proper divisors (21159).

33561 is a wasteful number, since it uses less digits than its factorization.

33561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 127 counting only the distinct ones).

The product of its digits is 270, while the sum is 18.

The square root of 33561 is about 183.1966156893. The cubic root of 33561 is about 32.2560832224.

The spelling of 33561 in words is "thirty-three thousand, five hundred sixty-one".