681618 has 16 divisors (see below), whose sum is σ = 1558080. Its totient is φ = 194736.

The previous prime is 681613. The next prime is 681623. The reversal of 681618 is 816186.

It is an interprime number because it is at equal distance from previous prime (681613) and next prime (681623).

It is not an unprimeable number, because it can be changed into a prime (681613) by changing a digit.

681618 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8073 + ... + 8156.

It is an arithmetic number, because the mean of its divisors is an integer number (97380).

2⁶⁸¹⁶¹⁸ is an apocalyptic number.

681618 is an abundant number, since it is smaller than the sum of its proper divisors (876462).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

681618 is a wasteful number, since it uses less digits than its factorization.

681618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16241.

The product of its digits is 2304, while the sum is 30.

The square root of 681618 is about 825.6015988357. The cubic root of 681618 is about 88.0062839865.

The spelling of 681618 in words is "six hundred eighty-one thousand, six hundred eighteen".