20505043231 has 2 divisors, whose sum is σ = 20505043232. Its totient is φ = 20505043230.

The previous prime is 20505043159. The next prime is 20505043259. The reversal of 20505043231 is 13234050502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20505043231 - 2²³ = 20496654623 is a prime.

It is a super-2 number, since 2×20505043231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20505043196 and 20505043205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20505043271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10252521615 + 10252521616.

It is an arithmetic number, because the mean of its divisors is an integer number (10252521616).

Almost surely, 2^20505043231 is an apocalyptic number.

20505043231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20505043231 is an equidigital number, since it uses as much as digits as its factorization.

20505043231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 25.

Adding to 20505043231 its reverse (13234050502), we get a palindrome (33739093733).

The spelling of 20505043231 in words is "twenty billion, five hundred five million, forty-three thousand, two hundred thirty-one".