21444400 has 30 divisors (see below), whose sum is σ = 51521132. Its totient is φ = 8577600.

The previous prime is 21444389. The next prime is 21444413. The reversal of 21444400 is 444412.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 26406 + ... + 27205.

Almost surely, 2^21444400 is an apocalyptic number.

21444400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21444400 is an abundant number, since it is smaller than the sum of its proper divisors (30076732).

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

21444400 is a wasteful number, since it uses less digits than its factorization.

21444400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53629 (or 53618 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

The square root of 21444400 is about 4630.8098643758. The cubic root of 21444400 is about 277.8249851620.

Adding to 21444400 its reverse (444412), we get a palindrome (21888812).

The spelling of 21444400 in words is "twenty-one million, four hundred forty-four thousand, four hundred".