681811 has 8 divisors (see below), whose sum is σ = 740880. Its totient is φ = 623712.

The previous prime is 681809. The next prime is 681823. The reversal of 681811 is 118186.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 681811 - 2¹ = 681809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681841) 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 in 7 ways as a sum of consecutive naturals, for example, 2181 + ... + 2473.

It is an arithmetic number, because the mean of its divisors is an integer number (92610).

2⁶⁸¹⁸¹¹ is an apocalyptic number.

681811 is a deficient number, since it is larger than the sum of its proper divisors (59069).

681811 is a wasteful number, since it uses less digits than its factorization.

681811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485.

The product of its digits is 384, while the sum is 25.

The square root of 681811 is about 825.7184750264. The cubic root of 681811 is about 88.0145895232.

Adding to 681811 its reverse (118186), we get a palindrome (799997).

The spelling of 681811 in words is "six hundred eighty-one thousand, eight hundred eleven".