68438189681 has 2 divisors, whose sum is σ = 68438189682. Its totient is φ = 68438189680.

The previous prime is 68438189663. The next prime is 68438189693. The reversal of 68438189681 is 18698183486.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46551946081 + 21886243600 = 215759^2 + 147940^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68438189681 is a prime.

It is a super-2 number, since 2×68438189681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (68438189621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34219094840 + 34219094841.

It is an arithmetic number, because the mean of its divisors is an integer number (34219094841).

Almost surely, 2^68438189681 is an apocalyptic number.

It is an amenable number.

68438189681 is a deficient number, since it is larger than the sum of its proper divisors (1).

68438189681 is an equidigital number, since it uses as much as digits as its factorization.

68438189681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15925248, while the sum is 62.

The spelling of 68438189681 in words is "sixty-eight billion, four hundred thirty-eight million, one hundred eighty-nine thousand, six hundred eighty-one".