21833840 has 80 divisors (see below), whose sum is σ = 58662912. Its totient is φ = 7402752.

The previous prime is 21833821. The next prime is 21833857. The reversal of 21833840 is 4833812.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70967 + ... + 71273.

Almost surely, 2^21833840 is an apocalyptic number.

21833840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21833840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29331456).

21833840 is an abundant number, since it is smaller than the sum of its proper divisors (36829072).

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

21833840 is a wasteful number, since it uses less digits than its factorization.

21833840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454 (or 448 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21833840 is about 4672.6694725820. The cubic root of 21833840 is about 279.4967149617.

The spelling of 21833840 in words is "twenty-one million, eight hundred thirty-three thousand, eight hundred forty".