68517582821 has 2 divisors, whose sum is σ = 68517582822. Its totient is φ = 68517582820.

The previous prime is 68517582769. The next prime is 68517582829. The reversal of 68517582821 is 12828571586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65405505025 + 3112077796 = 255745^2 + 55786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68517582821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68517582829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34258791410 + 34258791411.

It is an arithmetic number, because the mean of its divisors is an integer number (34258791411).

Almost surely, 2^68517582821 is an apocalyptic number.

It is an amenable number.

68517582821 is a deficient number, since it is larger than the sum of its proper divisors (1).

68517582821 is an equidigital number, since it uses as much as digits as its factorization.

68517582821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2150400, while the sum is 53.

The spelling of 68517582821 in words is "sixty-eight billion, five hundred seventeen million, five hundred eighty-two thousand, eight hundred twenty-one".