21643504360 has 64 divisors (see below), whose sum is σ = 50304499200. Its totient is φ = 8372179200.

The previous prime is 21643504343. The next prime is 21643504361. The reversal of 21643504360 is 6340534612.

It is not an unprimeable number, because it can be changed into a prime (21643504361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2002170 + ... + 2012950.

It is an arithmetic number, because the mean of its divisors is an integer number (786007800).

Almost surely, 2^21643504360 is an apocalyptic number.

21643504360 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 21643504360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25152249600).

21643504360 is an abundant number, since it is smaller than the sum of its proper divisors (28660994840).

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

21643504360 is a wasteful number, since it uses less digits than its factorization.

21643504360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12442 (or 12438 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 34.

The spelling of 21643504360 in words is "twenty-one billion, six hundred forty-three million, five hundred four thousand, three hundred sixty".