21309050880 has 312 divisors, whose sum is σ = 79553023368. Its totient is φ = 5244715008.

The previous prime is 21309050857. The next prime is 21309050881. The reversal of 21309050880 is 8805090312.

It can be written as a sum of positive squares in 4 ways, for example, as 128323584 + 21180727296 = 11328^2 + 145536^2 .

It is a tau number, because it is divible by the number of its divisors (312).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21309050881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2391714 + ... + 2400606.

It is an arithmetic number, because the mean of its divisors is an integer number (254977639).

Almost surely, 2^21309050880 is an apocalyptic number.

21309050880 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 21309050880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39776511684).

21309050880 is an abundant number, since it is smaller than the sum of its proper divisors (58243972488).

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

21309050880 is a wasteful number, since it uses less digits than its factorization.

21309050880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8941 (or 8916 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 21309050880 in words is "twenty-one billion, three hundred nine million, fifty thousand, eight hundred eighty".