681871 has 4 divisors (see below), whose sum is σ = 698544. Its totient is φ = 665200.

The previous prime is 681841. The next prime is 681883. The reversal of 681871 is 178186.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 681871 - 2⁵ = 681839 is a prime.

It is a Duffinian number.

681871 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8275 + ... + 8356.

It is an arithmetic number, because the mean of its divisors is an integer number (174636).

2⁶⁸¹⁸⁷¹ is an apocalyptic number.

681871 is a deficient number, since it is larger than the sum of its proper divisors (16673).

681871 is a wasteful number, since it uses less digits than its factorization.

681871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16672.

The product of its digits is 2688, while the sum is 31.

The square root of 681871 is about 825.7548062228. The cubic root of 681871 is about 88.0171712360.

It can be divided in two parts, 6818 and 71, that added together give a square (6889 = 83²).

The spelling of 681871 in words is "six hundred eighty-one thousand, eight hundred seventy-one".