33121638 has 36 divisors (see below), whose sum is σ = 78479388. Its totient is φ = 10012320.

The previous prime is 33121591. The next prime is 33121639. The reversal of 33121638 is 83612133.

It is a happy number.

33121638 is a `hidden beast` number, since 3 + 3 + 1 + 21 + 638 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (33121639) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 80778 + ... + 81186.

It is an arithmetic number, because the mean of its divisors is an integer number (2179983).

Almost surely, 2^33121638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 33121638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39239694).

33121638 is an abundant number, since it is smaller than the sum of its proper divisors (45357750).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

33121638 is a wasteful number, since it uses less digits than its factorization.

33121638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837 (or 425 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 33121638 is about 5755.1401373033. The cubic root of 33121638 is about 321.1470488237.

It can be divided in two parts, 3312 and 1638, that added together give a triangular number (4950 = T₉₉).

The spelling of 33121638 in words is "thirty-three million, one hundred twenty-one thousand, six hundred thirty-eight".