20431535105543 has 4 divisors (see below), whose sum is σ = 20449826543640. Its totient is φ = 20413243667448.

The previous prime is 20431535105533. The next prime is 20431535105711. The reversal of 20431535105543 is 34550153513402.

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 20431535105543 - 2¹⁸ = 20431534843399 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20431535105543.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20431535105533) 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 3 ways as a sum of consecutive naturals, for example, 9145717373 + ... + 9145719606.

It is an arithmetic number, because the mean of its divisors is an integer number (5112456635910).

Almost surely, 2^{20431535105543} is an apocalyptic number.

20431535105543 is a deficient number, since it is larger than the sum of its proper divisors (18291438097).

20431535105543 is a wasteful number, since it uses less digits than its factorization.

20431535105543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18291438096.

The product of its (nonzero) digits is 540000, while the sum is 41.

Adding to 20431535105543 its reverse (34550153513402), we get a palindrome (54981688618945).

The spelling of 20431535105543 in words is "twenty trillion, four hundred thirty-one billion, five hundred thirty-five million, one hundred five thousand, five hundred forty-three".