20518365823 has 2 divisors, whose sum is σ = 20518365824. Its totient is φ = 20518365822.

The previous prime is 20518365821. The next prime is 20518365859. The reversal of 20518365823 is 32856381502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20518365823 - 2¹ = 20518365821 is a prime.

Together with 20518365821, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20518365823.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20518365821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10259182911 + 10259182912.

It is an arithmetic number, because the mean of its divisors is an integer number (10259182912).

Almost surely, 2^20518365823 is an apocalyptic number.

20518365823 is a deficient number, since it is larger than the sum of its proper divisors (1).

20518365823 is an equidigital number, since it uses as much as digits as its factorization.

20518365823 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 345600, while the sum is 43.

The spelling of 20518365823 in words is "twenty billion, five hundred eighteen million, three hundred sixty-five thousand, eight hundred twenty-three".