21806981352 has 192 divisors, whose sum is σ = 68829022080. Its totient is φ = 6417937152.

The previous prime is 21806981351. The next prime is 21806981411. The reversal of 21806981352 is 25318960812.

21806981352 is a `hidden beast` number, since 218 + 0 + 6 + 9 + 81 + 352 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21806981298 and 21806981307.

It is not an unprimeable number, because it can be changed into a prime (21806981351) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 562498 + ... + 600014.

It is an arithmetic number, because the mean of its divisors is an integer number (358484490).

Almost surely, 2^21806981352 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 21806981352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34414511040).

21806981352 is an abundant number, since it is smaller than the sum of its proper divisors (47022040728).

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

21806981352 is a wasteful number, since it uses less digits than its factorization.

21806981352 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37574 (or 37558 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 21806981352 in words is "twenty-one billion, eight hundred six million, nine hundred eighty-one thousand, three hundred fifty-two".