21113680656 has 80 divisors (see below), whose sum is σ = 55759359744. Its totient is φ = 6881329152.

The previous prime is 21113680639. The next prime is 21113680657. The reversal of 21113680656 is 65608631112.

It is not an unprimeable number, because it can be changed into a prime (21113680657) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2597110 + ... + 2605226.

Almost surely, 2^21113680656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21113680656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27879679872).

21113680656 is an abundant number, since it is smaller than the sum of its proper divisors (34645679088).

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

21113680656 is a wasteful number, since it uses less digits than its factorization.

21113680656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9328 (or 9322 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The spelling of 21113680656 in words is "twenty-one billion, one hundred thirteen million, six hundred eighty thousand, six hundred fifty-six".