681823 has 2 divisors, whose sum is σ = 681824. Its totient is φ = 681822.

The previous prime is 681809. The next prime is 681833. The reversal of 681823 is 328186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681823 - 2⁹ = 681311 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 681791 and 681800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681833) 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, 340911 + 340912.

It is an arithmetic number, because the mean of its divisors is an integer number (340912).

2⁶⁸¹⁸²³ is an apocalyptic number.

681823 is a deficient number, since it is larger than the sum of its proper divisors (1).

681823 is an equidigital number, since it uses as much as digits as its factorization.

681823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 28.

The square root of 681823 is about 825.7257413936. The cubic root of 681823 is about 88.0151058779.

It can be divided in two parts, 68 and 1823, that added together give a triangular number (1891 = T₆₁).

The spelling of 681823 in words is "six hundred eighty-one thousand, eight hundred twenty-three".