68291811661 has 2 divisors, whose sum is σ = 68291811662. Its totient is φ = 68291811660.

The previous prime is 68291811659. The next prime is 68291811671. The reversal of 68291811661 is 16611819286.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60493862025 + 7797949636 = 245955^2 + 88306^2 .

It is a cyclic number.

It is not a de Polignac number, because 68291811661 - 2¹ = 68291811659 is a prime.

Together with 68291811659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68291811611) 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, 34145905830 + 34145905831.

It is an arithmetic number, because the mean of its divisors is an integer number (34145905831).

Almost surely, 2^68291811661 is an apocalyptic number.

It is an amenable number.

68291811661 is a deficient number, since it is larger than the sum of its proper divisors (1).

68291811661 is an equidigital number, since it uses as much as digits as its factorization.

68291811661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 248832, while the sum is 49.

The spelling of 68291811661 in words is "sixty-eight billion, two hundred ninety-one million, eight hundred eleven thousand, six hundred sixty-one".