681591 has 8 divisors (see below), whose sum is σ = 922624. Its totient is φ = 447480.

The previous prime is 681589. The next prime is 681607. The reversal of 681591 is 195186.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 681591 - 2¹ = 681589 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 (681521) 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, 1495 + ... + 1896.

It is an arithmetic number, because the mean of its divisors is an integer number (115328).

2⁶⁸¹⁵⁹¹ is an apocalyptic number.

681591 is a deficient number, since it is larger than the sum of its proper divisors (241033).

681591 is a wasteful number, since it uses less digits than its factorization.

681591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3461.

The product of its digits is 2160, while the sum is 30.

The square root of 681591 is about 825.5852469612. The cubic root of 681591 is about 88.0051219471.

The spelling of 681591 in words is "six hundred eighty-one thousand, five hundred ninety-one".