21324800 has 198 divisors, whose sum is σ = 65106882. Its totient is φ = 6881280.

The previous prime is 21324791. The next prime is 21324803. The reversal of 21324800 is 842312.

It can be written as a sum of positive squares in 3 ways, for example, as 3211264 + 18113536 = 1792^2 + 4256^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (21324803) by changing a digit.

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 17 ways as a sum of consecutive naturals, for example, 1254392 + ... + 1254408.

Almost surely, 2^21324800 is an apocalyptic number.

21324800 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 21324800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32553441).

21324800 is an abundant number, since it is smaller than the sum of its proper divisors (43782082).

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

21324800 is a wasteful number, since it uses less digits than its factorization.

21324800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61 (or 31 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 21324800 is about 4617.8783006918. The cubic root of 21324800 is about 277.3075255406.

The spelling of 21324800 in words is "twenty-one million, three hundred twenty-four thousand, eight hundred".