20909606543 has 4 divisors (see below), whose sum is σ = 23896693200. Its totient is φ = 17922519888.

The previous prime is 20909606513. The next prime is 20909606551. The reversal of 20909606543 is 34560690902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34560690902 = 2 ⋅17280345451.

It is not a de Polignac number, because 20909606543 - 2⁶ = 20909606479 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20909606494 and 20909606503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20909606503) 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, 1493543318 + ... + 1493543331.

It is an arithmetic number, because the mean of its divisors is an integer number (5974173300).

Almost surely, 2^20909606543 is an apocalyptic number.

20909606543 is a deficient number, since it is larger than the sum of its proper divisors (2987086657).

20909606543 is an equidigital number, since it uses as much as digits as its factorization.

20909606543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2987086656.

The product of its (nonzero) digits is 349920, while the sum is 44.

The spelling of 20909606543 in words is "twenty billion, nine hundred nine million, six hundred six thousand, five hundred forty-three".