21067318784 has 80 divisors (see below), whose sum is σ = 42786770400. Its totient is φ = 10360995840.

The previous prime is 21067318777. The next prime is 21067318787. The reversal of 21067318784 is 48781376012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21067318787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22387754 + ... + 22388694.

It is an arithmetic number, because the mean of its divisors is an integer number (534834630).

Almost surely, 2^21067318784 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 21067318784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21393385200).

21067318784 is an abundant number, since it is smaller than the sum of its proper divisors (21719451616).

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

21067318784 is an frugal number, since it uses more digits than its factorization.

21067318784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631 (or 1615 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 47.

The spelling of 21067318784 in words is "twenty-one billion, sixty-seven million, three hundred eighteen thousand, seven hundred eighty-four".