21447379968 has 264 divisors, whose sum is σ = 70007400000. Its totient is φ = 5804531712.

The previous prime is 21447379939. The next prime is 21447379969. The reversal of 21447379968 is 86997374412.

It is not an unprimeable number, because it can be changed into a prime (21447379969) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2856283 + ... + 2863781.

Almost surely, 2^21447379968 is an apocalyptic number.

21447379968 is a gapful number since it is divisible by the number (28) 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 21447379968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35003700000).

21447379968 is an abundant number, since it is smaller than the sum of its proper divisors (48560020032).

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

21447379968 is a wasteful number, since it uses less digits than its factorization.

21447379968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7555 (or 7530 counting only the distinct ones).

The product of its digits is 18289152, while the sum is 60.

The spelling of 21447379968 in words is "twenty-one billion, four hundred forty-seven million, three hundred seventy-nine thousand, nine hundred sixty-eight".