21682808 has 32 divisors (see below), whose sum is σ = 47164800. Its totient is φ = 9152352.

The previous prime is 21682757. The next prime is 21682823. The reversal of 21682808 is 80828612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 863 + ... + 6641.

It is an arithmetic number, because the mean of its divisors is an integer number (1473900).

Almost surely, 2^21682808 is an apocalyptic number.

21682808 is a gapful number since it is divisible by the number (28) 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 21682808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23582400).

21682808 is an abundant number, since it is smaller than the sum of its proper divisors (25481992).

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

21682808 is a wasteful number, since it uses less digits than its factorization.

21682808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5859 (or 5855 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 35.

The square root of 21682808 is about 4656.4802157853. The cubic root of 21682808 is about 278.8507657173.

The spelling of 21682808 in words is "twenty-one million, six hundred eighty-two thousand, eight hundred eight".