21304800 has 216 divisors, whose sum is σ = 82260360. Its totient is φ = 5145600.

The previous prime is 21304793. The next prime is 21304807. The reversal of 21304800 is 840312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21304793) and next prime (21304807).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304807) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 79066 + ... + 79334.

It is an arithmetic number, because the mean of its divisors is an integer number (380835).

Almost surely, 2^21304800 is an apocalyptic number.

21304800 is a gapful number since it is divisible by the number (20) 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 21304800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41130180).

21304800 is an abundant number, since it is smaller than the sum of its proper divisors (60955560).

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

21304800 is a wasteful number, since it uses less digits than its factorization.

21304800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306 (or 290 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21304800 is about 4615.7122960601. The cubic root of 21304800 is about 277.2208051450.

The spelling of 21304800 in words is "twenty-one million, three hundred four thousand, eight hundred".