21806559543 has 8 divisors (see below), whose sum is σ = 29077122928. Its totient is φ = 14536851264.

The previous prime is 21806559457. The next prime is 21806559557. The reversal of 21806559543 is 34595560812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21806559543 - 2⁸ = 21806559287 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21806559492 and 21806559501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21806559143) 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, 151696 + ... + 258117.

It is an arithmetic number, because the mean of its divisors is an integer number (3634640366).

Almost surely, 2^21806559543 is an apocalyptic number.

21806559543 is a deficient number, since it is larger than the sum of its proper divisors (7270563385).

21806559543 is a wasteful number, since it uses less digits than its factorization.

21806559543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427553.

The product of its (nonzero) digits is 1296000, while the sum is 48.

The spelling of 21806559543 in words is "twenty-one billion, eight hundred six million, five hundred fifty-nine thousand, five hundred forty-three".