21947008 has 32 divisors (see below), whose sum is σ = 45141120. Its totient is φ = 10617600.

The previous prime is 21946999. The next prime is 21947027. The reversal of 21947008 is 80074912.

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (31).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1203 + ... + 6733.

It is an arithmetic number, because the mean of its divisors is an integer number (1410660).

Almost surely, 2^21947008 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 21947008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22570560).

21947008 is an abundant number, since it is smaller than the sum of its proper divisors (23194112).

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

21947008 is an equidigital number, since it uses as much as digits as its factorization.

21947008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5576 (or 5564 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21947008 is about 4684.7633878351. The cubic root of 21947008 is about 279.9787739011.

The spelling of 21947008 in words is "twenty-one million, nine hundred forty-seven thousand, eight".