21303385780 has 48 divisors (see below), whose sum is σ = 47504696400. Its totient is φ = 7997073408.

The previous prime is 21303385709. The next prime is 21303385837. The reversal of 21303385780 is 8758330312.

It can be written as a sum of positive squares in 8 ways, for example, as 120912016 + 21182473764 = 10996^2 + 145542^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28894 + ... + 208426.

It is an arithmetic number, because the mean of its divisors is an integer number (989681175).

Almost surely, 2^21303385780 is an apocalyptic number.

21303385780 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 21303385780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23752348200).

21303385780 is an abundant number, since it is smaller than the sum of its proper divisors (26201310620).

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

21303385780 is a wasteful number, since it uses less digits than its factorization.

21303385780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179908 (or 179906 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 21303385780 in words is "twenty-one billion, three hundred three million, three hundred eighty-five thousand, seven hundred eighty".