68920981 has 2 divisors, whose sum is σ = 68920982. Its totient is φ = 68920980.

The previous prime is 68920937. The next prime is 68920997. The reversal of 68920981 is 18902986.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61308900 + 7612081 = 7830^2 + 2759^2 .

It is a cyclic number.

It is not a de Polignac number, because 68920981 - 2⁷ = 68920853 is a prime.

It is a super-2 number, since 2×68920981² = 9500203244004722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68920921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34460490 + 34460491.

It is an arithmetic number, because the mean of its divisors is an integer number (34460491).

Almost surely, 2^68920981 is an apocalyptic number.

It is an amenable number.

68920981 is a deficient number, since it is larger than the sum of its proper divisors (1).

68920981 is an equidigital number, since it uses as much as digits as its factorization.

68920981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 68920981 is about 8301.8661155188. The cubic root of 68920981 is about 409.9999623240. Note that the first 4 decimals are identical.

The spelling of 68920981 in words is "sixty-eight million, nine hundred twenty thousand, nine hundred eighty-one".