681648 has 40 divisors (see below), whose sum is σ = 1922496. Its totient is φ = 206400.

The previous prime is 681647. The next prime is 681673. The reversal of 681648 is 846186.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a nude number because it is divisible by every one of its digits.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 118 + ... + 1173.

2⁶⁸¹⁶⁴⁸ 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 681648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (961248).

681648 is an abundant number, since it is smaller than the sum of its proper divisors (1240848).

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

681648 is a wasteful number, since it uses less digits than its factorization.

681648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1313 (or 1307 counting only the distinct ones).

The product of its digits is 9216, while the sum is 33.

The square root of 681648 is about 825.6197672052. The cubic root of 681648 is about 88.0075751055.

The spelling of 681648 in words is "six hundred eighty-one thousand, six hundred forty-eight".