683605781 has 2 divisors, whose sum is σ = 683605782. Its totient is φ = 683605780.

The previous prime is 683605763. The next prime is 683605823. The reversal of 683605781 is 187506386.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 449821681 + 233784100 = 21209^2 + 15290^2 .

It is a cyclic number.

It is not a de Polignac number, because 683605781 - 2²⁶ = 616496917 is a prime.

It is a super-2 number, since 2×683605781² = 934633727633239922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (683605721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 341802890 + 341802891.

It is an arithmetic number, because the mean of its divisors is an integer number (341802891).

Almost surely, 2^683605781 is an apocalyptic number.

It is an amenable number.

683605781 is a deficient number, since it is larger than the sum of its proper divisors (1).

683605781 is an equidigital number, since it uses as much as digits as its factorization.

683605781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 44.

The square root of 683605781 is about 26145.8559049039. The cubic root of 683605781 is about 880.9175093895.

The spelling of 683605781 in words is "six hundred eighty-three million, six hundred five thousand, seven hundred eighty-one".