687831 has 8 divisors (see below), whose sum is σ = 925680. Its totient is φ = 454272.

The previous prime is 687829. The next prime is 687839. The reversal of 687831 is 138786.

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

It is not a de Polignac number, because 687831 - 2¹ = 687829 is a prime.

It is a super-2 number, since 2×687831² = 946222969122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 687792 and 687801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687839) 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, 676 + ... + 1353.

It is an arithmetic number, because the mean of its divisors is an integer number (115710).

2⁶⁸⁷⁸³¹ is an apocalyptic number.

687831 is a deficient number, since it is larger than the sum of its proper divisors (237849).

687831 is a wasteful number, since it uses less digits than its factorization.

687831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2145.

The product of its digits is 8064, while the sum is 33.

The square root of 687831 is about 829.3557740801. The cubic root of 687831 is about 88.2728702961.

The spelling of 687831 in words is "six hundred eighty-seven thousand, eight hundred thirty-one".