681536 has 28 divisors (see below), whose sum is σ = 1414272. Its totient is φ = 325248.

The previous prime is 681523. The next prime is 681539. The reversal of 681536 is 635186.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 681499 and 681508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1241 + ... + 1703.

2⁶⁸¹⁵³⁶ 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 681536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (707136).

681536 is an abundant number, since it is smaller than the sum of its proper divisors (732736).

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

681536 is a wasteful number, since it uses less digits than its factorization.

681536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498 (or 488 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 681536 is about 825.5519365855. The cubic root of 681536 is about 88.0027547347.

The spelling of 681536 in words is "six hundred eighty-one thousand, five hundred thirty-six".