21982812 has 48 divisors (see below), whose sum is σ = 53508000. Its totient is φ = 7015680.

The previous prime is 21982801. The next prime is 21982817. The reversal of 21982812 is 21828912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21982817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62814 + ... + 63162.

It is an arithmetic number, because the mean of its divisors is an integer number (1114750).

Almost surely, 2^21982812 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 21982812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26754000).

21982812 is an abundant number, since it is smaller than the sum of its proper divisors (31525188).

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

21982812 is a wasteful number, since it uses less digits than its factorization.

21982812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 566 (or 564 counting only the distinct ones).

The product of its digits is 4608, while the sum is 33.

The square root of 21982812 is about 4688.5831548561. The cubic root of 21982812 is about 280.1309421566.

The spelling of 21982812 in words is "twenty-one million, nine hundred eighty-two thousand, eight hundred twelve".