33661 has 4 divisors (see below), whose sum is σ = 34524. Its totient is φ = 32800.

The previous prime is 33647. The next prime is 33679. The reversal of 33661 is 16633.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4761 + 28900 = 69^2 + 170^2 .

It is not a de Polignac number, because 33661 - 2⁵ = 33629 is a prime.

It is a super-2 number, since 2×33661² = 2266125842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (33601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 370 + ... + 451.

It is an arithmetic number, because the mean of its divisors is an integer number (8631).

2³³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

33661 is a deficient number, since it is larger than the sum of its proper divisors (863).

33661 is an equidigital number, since it uses as much as digits as its factorization.

33661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 862.

The product of its digits is 324, while the sum is 19.

The square root of 33661 is about 183.4693434882. The cubic root of 33661 is about 32.2880887237.

The spelling of 33661 in words is "thirty-three thousand, six hundred sixty-one".