21685731996852 has 432 divisors, whose sum is σ = 70065078475392. Its totient is φ = 5494132869120.

The previous prime is 21685731996787. The next prime is 21685731996871. The reversal of 21685731996852 is 25869913758612.

21685731996852 is a `hidden beast` number, since 216 + 8 + 5 + 7 + 319 + 96 + 8 + 5 + 2 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 4392489328 + ... + 4392494264.

It is an arithmetic number, because the mean of its divisors is an integer number (162187681656).

Almost surely, 2^{21685731996852} is an apocalyptic number.

21685731996852 is a gapful number since it is divisible by the number (22) 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 21685731996852, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35032539237696).

21685731996852 is an abundant number, since it is smaller than the sum of its proper divisors (48379346478540).

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

21685731996852 is a wasteful number, since it uses less digits than its factorization.

21685731996852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5908 (or 5860 counting only the distinct ones).

The product of its digits is 391910400, while the sum is 72.

The spelling of 21685731996852 in words is "twenty-one trillion, six hundred eighty-five billion, seven hundred thirty-one million, nine hundred ninety-six thousand, eight hundred fifty-two".