20856548543 has 4 divisors (see below), whose sum is σ = 20908560288. Its totient is φ = 20804536800.

The previous prime is 20856548519. The next prime is 20856548551. The reversal of 20856548543 is 34584565802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20856548543 - 2¹⁴ = 20856532159 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20856548491 and 20856548500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20856548513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26005271 + ... + 26006072.

It is an arithmetic number, because the mean of its divisors is an integer number (5227140072).

Almost surely, 2^20856548543 is an apocalyptic number.

20856548543 is a deficient number, since it is larger than the sum of its proper divisors (52011745).

20856548543 is an equidigital number, since it uses as much as digits as its factorization.

20856548543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52011744.

The product of its (nonzero) digits is 4608000, while the sum is 50.

The spelling of 20856548543 in words is "twenty billion, eight hundred fifty-six million, five hundred forty-eight thousand, five hundred forty-three".