20718315738847 has 2 divisors, whose sum is σ = 20718315738848. Its totient is φ = 20718315738846.

The previous prime is 20718315738811. The next prime is 20718315738871. The reversal of 20718315738847 is 74883751381702.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20718315738847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20718315738877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10359157869423 + 10359157869424.

It is an arithmetic number, because the mean of its divisors is an integer number (10359157869424).

Almost surely, 2^{20718315738847} is an apocalyptic number.

20718315738847 is a deficient number, since it is larger than the sum of its proper divisors (1).

20718315738847 is an equidigital number, since it uses as much as digits as its factorization.

20718315738847 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 63221760, while the sum is 64.

The spelling of 20718315738847 in words is "twenty trillion, seven hundred eighteen billion, three hundred fifteen million, seven hundred thirty-eight thousand, eight hundred forty-seven".