21185680896 has 240 divisors, whose sum is σ = 64774854144. Its totient is φ = 6909732864.

The previous prime is 21185680847. The next prime is 21185680897. The reversal of 21185680896 is 69808658112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21185680897) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5845741 + ... + 5849363.

Almost surely, 2^21185680896 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 21185680896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32387427072).

21185680896 is an abundant number, since it is smaller than the sum of its proper divisors (43589173248).

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

21185680896 is an frugal number, since it uses more digits than its factorization.

21185680896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3703 (or 3675 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

The spelling of 21185680896 in words is "twenty-one billion, one hundred eighty-five million, six hundred eighty thousand, eight hundred ninety-six".