20559817243 has 6 divisors (see below), whose sum is σ = 23916522156. Its totient is φ = 17622700452.

The previous prime is 20559817189. The next prime is 20559817249. The reversal of 20559817243 is 34271895502.

It is not a de Polignac number, because 20559817243 - 2²⁵ = 20526262811 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20559817193 and 20559817202.

It is not an unprimeable number, because it can be changed into a prime (20559817249) 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 5 ways as a sum of consecutive naturals, for example, 209794005 + ... + 209794102.

It is an arithmetic number, because the mean of its divisors is an integer number (3986087026).

Almost surely, 2^20559817243 is an apocalyptic number.

20559817243 is a deficient number, since it is larger than the sum of its proper divisors (3356704913).

20559817243 is an equidigital number, since it uses as much as digits as its factorization.

20559817243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419588121 (or 419588114 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 46.

The spelling of 20559817243 in words is "twenty billion, five hundred fifty-nine million, eight hundred seventeen thousand, two hundred forty-three".