21396780384 has 192 divisors, whose sum is σ = 68523356160. Its totient is φ = 5709795840.

The previous prime is 21396780341. The next prime is 21396780389. The reversal of 21396780384 is 48308769312.

It is a super-2 number, since 2×21396780384² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21396780389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 894727 + ... + 918329.

It is an arithmetic number, because the mean of its divisors is an integer number (356892480).

Almost surely, 2^21396780384 is an apocalyptic number.

21396780384 is a gapful number since it is divisible by the number (24) 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 21396780384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34261678080).

21396780384 is an abundant number, since it is smaller than the sum of its proper divisors (47126575776).

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

21396780384 is a wasteful number, since it uses less digits than its factorization.

21396780384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23713 (or 23705 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 51.

The spelling of 21396780384 in words is "twenty-one billion, three hundred ninety-six million, seven hundred eighty thousand, three hundred eighty-four".