681559 has 4 divisors (see below), whose sum is σ = 711216. Its totient is φ = 651904.

The previous prime is 681557. The next prime is 681563. The reversal of 681559 is 955186.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 955186 = 2 ⋅477593.

It is a cyclic number.

It is not a de Polignac number, because 681559 - 2¹ = 681557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14794 + ... + 14839.

It is an arithmetic number, because the mean of its divisors is an integer number (177804).

2⁶⁸¹⁵⁵⁹ is an apocalyptic number.

681559 is a deficient number, since it is larger than the sum of its proper divisors (29657).

681559 is a wasteful number, since it uses less digits than its factorization.

681559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29656.

The product of its digits is 10800, while the sum is 34.

The square root of 681559 is about 825.5658665425. The cubic root of 681559 is about 88.0037446754.

The spelling of 681559 in words is "six hundred eighty-one thousand, five hundred fifty-nine".