21303232440 has 256 divisors, whose sum is σ = 81407462400. Its totient is φ = 4341620736.

The previous prime is 21303232411. The next prime is 21303232471. The reversal of 21303232440 is 4423230312.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21303232440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 232062 + ... + 310578.

It is an arithmetic number, because the mean of its divisors is an integer number (317997900).

Almost surely, 2^21303232440 is an apocalyptic number.

21303232440 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 21303232440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40703731200).

21303232440 is an abundant number, since it is smaller than the sum of its proper divisors (60104229960).

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

21303232440 is a wasteful number, since it uses less digits than its factorization.

21303232440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78574 (or 78570 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 24.

Adding to 21303232440 its reverse (4423230312), we get a palindrome (25726462752).

The spelling of 21303232440 in words is "twenty-one billion, three hundred three million, two hundred thirty-two thousand, four hundred forty".