21303616640 has 256 divisors, whose sum is σ = 56408970240. Its totient is φ = 7657881600.

The previous prime is 21303616603. The next prime is 21303616673. The reversal of 21303616640 is 4661630312.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 21303616597 and 21303616606.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27993860 + ... + 27994620.

It is an arithmetic number, because the mean of its divisors is an integer number (220347540).

Almost surely, 2^21303616640 is an apocalyptic number.

21303616640 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 21303616640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28204485120).

21303616640 is an abundant number, since it is smaller than the sum of its proper divisors (35105353600).

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

21303616640 is a wasteful number, since it uses less digits than its factorization.

21303616640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 911 (or 899 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 32.

The spelling of 21303616640 in words is "twenty-one billion, three hundred three million, six hundred sixteen thousand, six hundred forty".