681568 has 36 divisors (see below), whose sum is σ = 1440180. Its totient is φ = 317376.

The previous prime is 681563. The next prime is 681589. The reversal of 681568 is 865186.

It is a happy number.

Its product of digits (11520) is a multiple of the sum of its prime divisors (80).

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681563) by changing a digit.

681568 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 5 ways as a sum of consecutive naturals, for example, 11523 + ... + 11581.

It is an arithmetic number, because the mean of its divisors is an integer number (40005).

2⁶⁸¹⁵⁶⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (720090).

681568 is an abundant number, since it is smaller than the sum of its proper divisors (758612).

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

681568 is a wasteful number, since it uses less digits than its factorization.

681568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107 (or 80 counting only the distinct ones).

The product of its digits is 11520, while the sum is 34.

The square root of 681568 is about 825.5713173312. The cubic root of 681568 is about 88.0041320374.

The spelling of 681568 in words is "six hundred eighty-one thousand, five hundred sixty-eight".