20317345767821 has 2 divisors, whose sum is σ = 20317345767822. Its totient is φ = 20317345767820.

The previous prime is 20317345767773. The next prime is 20317345767827. The reversal of 20317345767821 is 12876754371302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20244699346921 + 72646420900 = 4499411^2 + 269530^2 .

It is a cyclic number.

It is not a de Polignac number, because 20317345767821 - 2¹⁰ = 20317345766797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20317345767827) 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 as a sum of consecutive naturals, namely, 10158672883910 + 10158672883911.

It is an arithmetic number, because the mean of its divisors is an integer number (10158672883911).

Almost surely, 2^{20317345767821} is an apocalyptic number.

It is an amenable number.

20317345767821 is a deficient number, since it is larger than the sum of its proper divisors (1).

20317345767821 is an equidigital number, since it uses as much as digits as its factorization.

20317345767821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11854080, while the sum is 56.

The spelling of 20317345767821 in words is "twenty trillion, three hundred seventeen billion, three hundred forty-five million, seven hundred sixty-seven thousand, eight hundred twenty-one".