21984340784 has 40 divisors (see below), whose sum is σ = 49673085600. Its totient is φ = 9421857984.

The previous prime is 21984340783. The next prime is 21984340831. The reversal of 21984340784 is 48704348912.

It is a happy number.

It is a super-2 number, since 2×21984340784² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21984340783) 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, 1997459 + ... + 2008434.

It is an arithmetic number, because the mean of its divisors is an integer number (1241827140).

Almost surely, 2^21984340784 is an apocalyptic number.

It is an amenable number.

21984340784 is an abundant number, since it is smaller than the sum of its proper divisors (27688744816).

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

21984340784 is an equidigital number, since it uses as much as digits as its factorization.

21984340784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4005922 (or 4005902 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 50.

The spelling of 21984340784 in words is "twenty-one billion, nine hundred eighty-four million, three hundred forty thousand, seven hundred eighty-four".