685819 has 2 divisors, whose sum is σ = 685820. Its totient is φ = 685818.

The previous prime is 685793. The next prime is 685849. The reversal of 685819 is 918586.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 685819 - 2¹³ = 677627 is a prime.

It is a super-2 number, since 2×685819² = 940695401522, which contains 22 as substring.

It is a nialpdrome in base 7.

It is not a weakly prime, because it can be changed into another prime (685849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342909 + 342910.

It is an arithmetic number, because the mean of its divisors is an integer number (342910).

2⁶⁸⁵⁸¹⁹ is an apocalyptic number.

685819 is a deficient number, since it is larger than the sum of its proper divisors (1).

685819 is an equidigital number, since it uses as much as digits as its factorization.

685819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 37.

The square root of 685819 is about 828.1418960541. The cubic root of 685819 is about 88.1867161535.

The spelling of 685819 in words is "six hundred eighty-five thousand, eight hundred nineteen".