20391808793 has 2 divisors, whose sum is σ = 20391808794. Its totient is φ = 20391808792.

The previous prime is 20391808747. The next prime is 20391808813. The reversal of 20391808793 is 39780819302.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11425044544 + 8966764249 = 106888^2 + 94693^2 .

It is a cyclic number.

It is not a de Polignac number, because 20391808793 - 2¹⁰ = 20391807769 is a prime.

It is not a weakly prime, because it can be changed into another prime (20391858793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10195904396 + 10195904397.

It is an arithmetic number, because the mean of its divisors is an integer number (10195904397).

Almost surely, 2^20391808793 is an apocalyptic number.

It is an amenable number.

20391808793 is a deficient number, since it is larger than the sum of its proper divisors (1).

20391808793 is an equidigital number, since it uses as much as digits as its factorization.

20391808793 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 653184, while the sum is 50.

The spelling of 20391808793 in words is "twenty billion, three hundred ninety-one million, eight hundred eight thousand, seven hundred ninety-three".