21224800 has 72 divisors (see below), whose sum is σ = 53105976. Its totient is φ = 8279040.

The previous prime is 21224783. The next prime is 21224803. The reversal of 21224800 is 842212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224803) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34092 + ... + 34708.

It is an arithmetic number, because the mean of its divisors is an integer number (737583).

Almost surely, 2^21224800 is an apocalyptic number.

21224800 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 21224800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26552988).

21224800 is an abundant number, since it is smaller than the sum of its proper divisors (31881176).

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

21224800 is a wasteful number, since it uses less digits than its factorization.

21224800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680 (or 667 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 21224800 is about 4607.0380940470. The cubic root of 21224800 is about 276.8733798124.

The spelling of 21224800 in words is "twenty-one million, two hundred twenty-four thousand, eight hundred".