21113208 has 48 divisors (see below), whose sum is σ = 57886920. Its totient is φ = 6950976.

The previous prime is 21113173. The next prime is 21113221. The reversal of 21113208 is 80231112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4210 + ... + 7742.

Almost surely, 2^21113208 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21113208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28943460).

21113208 is an abundant number, since it is smaller than the sum of its proper divisors (36773712).

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

21113208 is a wasteful number, since it uses less digits than its factorization.

21113208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3628 (or 3621 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 21113208 is about 4594.9110981607. The cubic root of 21113208 is about 276.3872949663.

It can be divided in two parts, 21113 and 208, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 21113208 in words is "twenty-one million, one hundred thirteen thousand, two hundred eight".