21113239680 has 672 divisors, whose sum is σ = 82902104460. Its totient is φ = 5109018624.

The previous prime is 21113239669. The next prime is 21113239687. The reversal of 21113239680 is 8693231112.

It can be written as a sum of positive squares in 2 ways, for example, as 19651553856 + 1461685824 = 140184^2 + 38232^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21113239687) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 357851491 + ... + 357851549.

Almost surely, 2^21113239680 is an apocalyptic number.

21113239680 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 21113239680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41451052230).

21113239680 is an abundant number, since it is smaller than the sum of its proper divisors (61788864780).

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

21113239680 is an frugal number, since it uses more digits than its factorization.

21113239680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The spelling of 21113239680 in words is "twenty-one billion, one hundred thirteen million, two hundred thirty-nine thousand, six hundred eighty".