687631 has 8 divisors (see below), whose sum is σ = 820224. Its totient is φ = 563640.

The previous prime is 687623. The next prime is 687637. The reversal of 687631 is 136786.

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

It is not a de Polignac number, because 687631 - 2³ = 687623 is a prime.

It is a super-2 number, since 2×687631² = 945672784322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 687593 and 687602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687637) 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, 1975 + ... + 2296.

It is an arithmetic number, because the mean of its divisors is an integer number (102528).

2⁶⁸⁷⁶³¹ is an apocalyptic number.

687631 is a deficient number, since it is larger than the sum of its proper divisors (132593).

687631 is a wasteful number, since it uses less digits than its factorization.

687631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4301.

The product of its digits is 6048, while the sum is 31.

The square root of 687631 is about 829.2351897984. The cubic root of 687631 is about 88.2643137924.

The spelling of 687631 in words is "six hundred eighty-seven thousand, six hundred thirty-one".