685492109 has 2 divisors, whose sum is σ = 685492110. Its totient is φ = 685492108.

The previous prime is 685492097. The next prime is 685492117. The reversal of 685492109 is 901294586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 566202025 + 119290084 = 23795^2 + 10922^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685492109 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 685492109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685492009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342746054 + 342746055.

It is an arithmetic number, because the mean of its divisors is an integer number (342746055).

Almost surely, 2^685492109 is an apocalyptic number.

It is an amenable number.

685492109 is a deficient number, since it is larger than the sum of its proper divisors (1).

685492109 is an equidigital number, since it uses as much as digits as its factorization.

685492109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 685492109 is about 26181.9042279205. The cubic root of 685492109 is about 881.7270272572.

The spelling of 685492109 in words is "six hundred eighty-five million, four hundred ninety-two thousand, one hundred nine".