21956608 has 48 divisors (see below), whose sum is σ = 44815680. Its totient is φ = 10752000.

The previous prime is 21956603. The next prime is 21956611. The reversal of 21956608 is 80665912.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21956603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145333 + ... + 145483.

It is an arithmetic number, because the mean of its divisors is an integer number (933660).

Almost surely, 2^21956608 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 21956608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22407840).

21956608 is an abundant number, since it is smaller than the sum of its proper divisors (22859072).

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

21956608 is an equidigital number, since it uses as much as digits as its factorization.

21956608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 21956608 is about 4685.7878739866. The cubic root of 21956608 is about 280.0195904660.

The spelling of 21956608 in words is "twenty-one million, nine hundred fifty-six thousand, six hundred eight".