687730 has 16 divisors (see below), whose sum is σ = 1252440. Its totient is φ = 271872.

The previous prime is 687721. The next prime is 687737. The reversal of 687730 is 37786.

It can be written as a sum of positive squares in 4 ways, for example, as 405769 + 281961 = 637^2 + 531^2 .

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 687692 and 687701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687737) 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, 616 + ... + 1324.

2⁶⁸⁷⁷³⁰ is an apocalyptic number.

687730 is a deficient number, since it is larger than the sum of its proper divisors (564710).

687730 is a wasteful number, since it uses less digits than its factorization.

687730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 813.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 687730 is about 829.2948812093. The cubic root of 687730 is about 88.2685494690.

The spelling of 687730 in words is "six hundred eighty-seven thousand, seven hundred thirty".