33639981 has 8 divisors (see below), whose sum is σ = 44959104. Its totient is φ = 22373760.

The previous prime is 33639959. The next prime is 33639989. The reversal of 33639981 is 18993633.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 33639981 - 2¹⁵ = 33607213 is a prime.

It is a super-2 number, since 2×33639981² = 2263296643360722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (33639989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11716 + ... + 14301.

It is an arithmetic number, because the mean of its divisors is an integer number (5619888).

Almost surely, 2^33639981 is an apocalyptic number.

It is an amenable number.

33639981 is a deficient number, since it is larger than the sum of its proper divisors (11319123).

33639981 is a wasteful number, since it uses less digits than its factorization.

33639981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26451.

The product of its digits is 104976, while the sum is 42.

The square root of 33639981 is about 5799.9983620687. The cubic root of 33639981 is about 322.8136675421.

The spelling of 33639981 in words is "thirty-three million, six hundred thirty-nine thousand, nine hundred eighty-one".