21447609968640 has 192 divisors, whose sum is σ = 69322982863680. Its totient is φ = 5660399370240.

The previous prime is 21447609968627. The next prime is 21447609968657. The reversal of 21447609968640 is 4686990674412.

It is a tau number, because it is divible by the number of its divisors (192).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 618946 + ... + 6578625.

It is an arithmetic number, because the mean of its divisors is an integer number (361057202415).

Almost surely, 2^{21447609968640} is an apocalyptic number.

21447609968640 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 21447609968640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34661491431840).

21447609968640 is an abundant number, since it is smaller than the sum of its proper divisors (47875372895040).

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

21447609968640 is an equidigital number, since it uses as much as digits as its factorization.

21447609968640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7197698 (or 7197678 counting only the distinct ones).

The product of its (nonzero) digits is 125411328, while the sum is 66.

The spelling of 21447609968640 in words is "twenty-one trillion, four hundred forty-seven billion, six hundred nine million, nine hundred sixty-eight thousand, six hundred forty".