21351044320 has 96 divisors (see below), whose sum is σ = 51531076800. Its totient is φ = 8357437440.

The previous prime is 21351044317. The next prime is 21351044321. The reversal of 21351044320 is 2344015312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351044321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1936744 + ... + 1947736.

It is an arithmetic number, because the mean of its divisors is an integer number (536782050).

Almost surely, 2^21351044320 is an apocalyptic number.

21351044320 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 21351044320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25765538400).

21351044320 is an abundant number, since it is smaller than the sum of its proper divisors (30180032480).

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

21351044320 is a wasteful number, since it uses less digits than its factorization.

21351044320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11268 (or 11260 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 21351044320 its reverse (2344015312), we get a palindrome (23695059632).

The spelling of 21351044320 in words is "twenty-one billion, three hundred fifty-one million, forty-four thousand, three hundred twenty".