21244430400 has 84 divisors (see below), whose sum is σ = 69699451152. Its totient is φ = 5665180160.

The previous prime is 21244430381. The next prime is 21244430407. The reversal of 21244430400 is 403444212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21244430407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2208162 + ... + 2217761.

Almost surely, 2^21244430400 is an apocalyptic number.

21244430400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21244430400 is an abundant number, since it is smaller than the sum of its proper divisors (48455020752).

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

21244430400 is a wasteful number, since it uses less digits than its factorization.

21244430400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4425948 (or 4425933 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 24.

Adding to 21244430400 its reverse (403444212), we get a palindrome (21647874612).

The spelling of 21244430400 in words is "twenty-one billion, two hundred forty-four million, four hundred thirty thousand, four hundred".