21302304 has 48 divisors (see below), whose sum is σ = 56881440. Its totient is φ = 6978560.

The previous prime is 21302299. The next prime is 21302321. The reversal of 21302304 is 40320312.

It is a tau number, because it is divible by the number of its divisors (48).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3784 + ... + 7544.

It is an arithmetic number, because the mean of its divisors is an integer number (1185030).

Almost surely, 2^21302304 is an apocalyptic number.

21302304 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 21302304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28440720).

21302304 is an abundant number, since it is smaller than the sum of its proper divisors (35579136).

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

21302304 is a wasteful number, since it uses less digits than its factorization.

21302304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3833 (or 3825 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21302304 is about 4615.4419073367. The cubic root of 21302304 is about 277.2099786309.

Adding to 21302304 its reverse (40320312), we get a palindrome (61622616).

The spelling of 21302304 in words is "twenty-one million, three hundred two thousand, three hundred four".