21998304 has 168 divisors, whose sum is σ = 69409872. Its totient is φ = 6842880.

The previous prime is 21998299. The next prime is 21998309. The reversal of 21998304 is 40389912.

It is an interprime number because it is at equal distance from previous prime (21998299) and next prime (21998309).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21998309) by changing a digit.

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 27 ways as a sum of consecutive naturals, for example, 536524 + ... + 536564.

It is an arithmetic number, because the mean of its divisors is an integer number (413154).

Almost surely, 2^21998304 is an apocalyptic number.

21998304 is a gapful number since it is divisible by the number (24) 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 21998304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34704936).

21998304 is an abundant number, since it is smaller than the sum of its proper divisors (47411568).

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

21998304 is an equidigital number, since it uses as much as digits as its factorization.

21998304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92 (or 69 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 21998304 is about 4690.2349621314. The cubic root of 21998304 is about 280.1967324885.

The spelling of 21998304 in words is "twenty-one million, nine hundred ninety-eight thousand, three hundred four".