21113680640 has 144 divisors (see below), whose sum is σ = 54702345600. Its totient is φ = 7761739776.

The previous prime is 21113680639. The next prime is 21113680657. The reversal of 21113680640 is 4608631112.

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 = 21113680597 and 21113680606.

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, 3974306 + ... + 3979614.

It is an arithmetic number, because the mean of its divisors is an integer number (379877400).

Almost surely, 2^21113680640 is an apocalyptic number.

21113680640 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 21113680640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27351172800).

21113680640 is an abundant number, since it is smaller than the sum of its proper divisors (33588664960).

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

21113680640 is a wasteful number, since it uses less digits than its factorization.

21113680640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5582 (or 5568 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The spelling of 21113680640 in words is "twenty-one billion, one hundred thirteen million, six hundred eighty thousand, six hundred forty".