21533808 has 40 divisors (see below), whose sum is σ = 56016256. Its totient is φ = 7128000.

The previous prime is 21533807. The next prime is 21533843. The reversal of 21533808 is 80833512.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21533807) 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, 5763 + ... + 8733.

Almost surely, 2^21533808 is an apocalyptic number.

It is an amenable number.

21533808 is an abundant number, since it is smaller than the sum of its proper divisors (34482448).

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

21533808 is a wasteful number, since it uses less digits than its factorization.

21533808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3133 (or 3127 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 21533808 is about 4640.4534261212. The cubic root of 21533808 is about 278.2105611099.

The spelling of 21533808 in words is "twenty-one million, five hundred thirty-three thousand, eight hundred eight".