68818366781 has 2 divisors, whose sum is σ = 68818366782. Its totient is φ = 68818366780.

The previous prime is 68818366759. The next prime is 68818366789. The reversal of 68818366781 is 18766381886.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64663404100 + 4154962681 = 254290^2 + 64459^2 .

It is a cyclic number.

It is not a de Polignac number, because 68818366781 - 2²² = 68814172477 is a prime.

It is a super-2 number, since 2×68818366781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68818366789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34409183390 + 34409183391.

It is an arithmetic number, because the mean of its divisors is an integer number (34409183391).

Almost surely, 2^68818366781 is an apocalyptic number.

It is an amenable number.

68818366781 is a deficient number, since it is larger than the sum of its proper divisors (1).

68818366781 is an equidigital number, since it uses as much as digits as its factorization.

68818366781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18579456, while the sum is 62.

The spelling of 68818366781 in words is "sixty-eight billion, eight hundred eighteen million, three hundred sixty-six thousand, seven hundred eighty-one".