68181809 has 2 divisors, whose sum is σ = 68181810. Its totient is φ = 68181808.

The previous prime is 68181779. The next prime is 68181829. The reversal of 68181809 is 90818186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47679025 + 20502784 = 6905^2 + 4528^2 .

It is a cyclic number.

It is not a de Polignac number, because 68181809 - 2²⁰ = 67133233 is a prime.

It is not a weakly prime, because it can be changed into another prime (68181829) 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, 34090904 + 34090905.

It is an arithmetic number, because the mean of its divisors is an integer number (34090905).

Almost surely, 2^68181809 is an apocalyptic number.

It is an amenable number.

68181809 is a deficient number, since it is larger than the sum of its proper divisors (1).

68181809 is an equidigital number, since it uses as much as digits as its factorization.

68181809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 41.

The square root of 68181809 is about 8257.2276824610. The cubic root of 68181809 is about 408.5289519832.

The spelling of 68181809 in words is "sixty-eight million, one hundred eighty-one thousand, eight hundred nine".