68971781 has 2 divisors, whose sum is σ = 68971782. Its totient is φ = 68971780.

The previous prime is 68971769. The next prime is 68971841. The reversal of 68971781 is 18717986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66569281 + 2402500 = 8159^2 + 1550^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68971781 is a prime.

It is a super-2 number, since 2×68971781² = 9514213148623922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68971711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34485890 + 34485891.

It is an arithmetic number, because the mean of its divisors is an integer number (34485891).

Almost surely, 2^68971781 is an apocalyptic number.

It is an amenable number.

68971781 is a deficient number, since it is larger than the sum of its proper divisors (1).

68971781 is an equidigital number, since it uses as much as digits as its factorization.

68971781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 47.

The square root of 68971781 is about 8304.9251050205. The cubic root of 68971781 is about 410.1006712935.

The spelling of 68971781 in words is "sixty-eight million, nine hundred seventy-one thousand, seven hundred eighty-one".