681606 has 24 divisors (see below), whose sum is σ = 1555320. Its totient is φ = 215136.

The previous prime is 681589. The next prime is 681607. The reversal of 681606 is 606186.

It is a self number, because there is not a number n which added to its sum of digits gives 681606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681607) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 655 + ... + 1338.

It is an arithmetic number, because the mean of its divisors is an integer number (64805).

2⁶⁸¹⁶⁰⁶ is an apocalyptic number.

681606 is an abundant number, since it is smaller than the sum of its proper divisors (873714).

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

681606 is a wasteful number, since it uses less digits than its factorization.

681606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2020 (or 2017 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 681606 is about 825.5943313759. The cubic root of 681606 is about 88.0057675283.

It can be divided in two parts, 681 and 606, that multiplied together give a triangular number (412686 = T₉₀₈).

The spelling of 681606 in words is "six hundred eighty-one thousand, six hundred six".