21744008 has 64 divisors (see below), whose sum is σ = 48686400. Its totient is φ = 8974080.

The previous prime is 21744001. The next prime is 21744011. The reversal of 21744008 is 80044712.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (21744001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94838 + ... + 95066.

It is an arithmetic number, because the mean of its divisors is an integer number (760725).

Almost surely, 2^21744008 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 21744008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24343200).

21744008 is an abundant number, since it is smaller than the sum of its proper divisors (26942392).

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

21744008 is a wasteful number, since it uses less digits than its factorization.

21744008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 338 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21744008 is about 4663.0470724624. The cubic root of 21744008 is about 279.1128725436.

The spelling of 21744008 in words is "twenty-one million, seven hundred forty-four thousand, eight".