21402304 has 112 divisors (see below), whose sum is σ = 54717696. Its totient is φ = 8064000.

The previous prime is 21402299. The next prime is 21402323. The reversal of 21402304 is 40320412.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 211854 + ... + 211954.

Almost surely, 2^21402304 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 21402304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27358848).

21402304 is an abundant number, since it is smaller than the sum of its proper divisors (33315392).

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

21402304 is a wasteful number, since it uses less digits than its factorization.

21402304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174 (or 164 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21402304 is about 4626.2624223016. The cubic root of 21402304 is about 277.6430731525.

Adding to 21402304 its reverse (40320412), we get a palindrome (61722716).

It can be divided in two parts, 2140 and 2304, that added together give a palindrome (4444).

The spelling of 21402304 in words is "twenty-one million, four hundred two thousand, three hundred four".