21423886720 has 128 divisors (see below), whose sum is σ = 53278663680. Its totient is φ = 8228812800.

The previous prime is 21423886699. The next prime is 21423886721. The reversal of 21423886720 is 2768832412.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423886721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2594919 + ... + 2603161.

It is an arithmetic number, because the mean of its divisors is an integer number (416239560).

Almost surely, 2^21423886720 is an apocalyptic number.

21423886720 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 21423886720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26639331840).

21423886720 is an abundant number, since it is smaller than the sum of its proper divisors (31854776960).

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

21423886720 is a wasteful number, since it uses less digits than its factorization.

21423886720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8424 (or 8412 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 43.

The spelling of 21423886720 in words is "twenty-one billion, four hundred twenty-three million, eight hundred eighty-six thousand, seven hundred twenty".