21682521216720 has 800 divisors, whose sum is σ = 92792953870848. Its totient is φ = 4569448329216.

The previous prime is 21682521216701. The next prime is 21682521216731. The reversal of 21682521216720 is 2761212528612.

21682521216720 is a `hidden beast` number, since 2 + 1 + 6 + 82 + 521 + 21 + 6 + 7 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 517128397 + ... + 517170323.

Almost surely, 2^{21682521216720} is an apocalyptic number.

21682521216720 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 21682521216720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46396476935424).

21682521216720 is an abundant number, since it is smaller than the sum of its proper divisors (71110432654128).

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

21682521216720 is a wasteful number, since it uses less digits than its factorization.

21682521216720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42849 (or 42834 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 21682521216720 in words is "twenty-one trillion, six hundred eighty-two billion, five hundred twenty-one million, two hundred sixteen thousand, seven hundred twenty".