21447800000 has 168 divisors, whose sum is σ = 58039254000. Its totient is φ = 7798400000.

The previous prime is 21447799991. The next prime is 21447800029. The reversal of 21447800000 is 874412.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2195126 + ... + 2204874.

It is an arithmetic number, because the mean of its divisors is an integer number (345471750).

Almost surely, 2^21447800000 is an apocalyptic number.

21447800000 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 21447800000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29019627000).

21447800000 is an abundant number, since it is smaller than the sum of its proper divisors (36591454000).

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

21447800000 is an frugal number, since it uses more digits than its factorization.

21447800000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9797 (or 9767 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The spelling of 21447800000 in words is "twenty-one billion, four hundred forty-seven million, eight hundred thousand".