21653008 has 40 divisors (see below), whose sum is σ = 47566400. Its totient is φ = 9465984.

The previous prime is 21652997. The next prime is 21653011. The reversal of 21653008 is 80035612.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1213 + ... + 6691.

It is an arithmetic number, because the mean of its divisors is an integer number (1189160).

Almost surely, 2^21653008 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 21653008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23783200).

21653008 is an abundant number, since it is smaller than the sum of its proper divisors (25913392).

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

21653008 is a wasteful number, since it uses less digits than its factorization.

21653008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5519 (or 5513 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21653008 is about 4653.2792738025. The cubic root of 21653008 is about 278.7229599677.

The spelling of 21653008 in words is "twenty-one million, six hundred fifty-three thousand, eight".