68911681 has 2 divisors, whose sum is σ = 68911682. Its totient is φ = 68911680.

The previous prime is 68911637. The next prime is 68911697. The reversal of 68911681 is 18611986.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67568400 + 1343281 = 8220^2 + 1159^2 .

It is a cyclic number.

It is not a de Polignac number, because 68911681 - 2⁷ = 68911553 is a prime.

It is a super-2 number, since 2×68911681² = 9497639556491522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (68911631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34455840 + 34455841.

It is an arithmetic number, because the mean of its divisors is an integer number (34455841).

Almost surely, 2^68911681 is an apocalyptic number.

It is an amenable number.

68911681 is a deficient number, since it is larger than the sum of its proper divisors (1).

68911681 is an equidigital number, since it uses as much as digits as its factorization.

68911681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 40.

The square root of 68911681 is about 8301.3059815911. The cubic root of 68911681 is about 409.9815200872.

The spelling of 68911681 in words is "sixty-eight million, nine hundred eleven thousand, six hundred eighty-one".