681642 has 32 divisors (see below), whose sum is σ = 1632960. Its totient is φ = 209520.

The previous prime is 681631. The next prime is 681647. The reversal of 681642 is 246186.

681642 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (681647) by changing a digit.

681642 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 15 ways as a sum of consecutive naturals, for example, 217 + ... + 1187.

It is an arithmetic number, because the mean of its divisors is an integer number (51030).

2⁶⁸¹⁶⁴² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (816480).

681642 is an abundant number, since it is smaller than the sum of its proper divisors (951318).

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

681642 is a wasteful number, since it uses less digits than its factorization.

681642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995 (or 989 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 681642 is about 825.6161335633. The cubic root of 681642 is about 88.0073168847.

The spelling of 681642 in words is "six hundred eighty-one thousand, six hundred forty-two".