687128 has 16 divisors (see below), whose sum is σ = 1387680. Its totient is φ = 317088.

The previous prime is 687121. The next prime is 687131. The reversal of 687128 is 821786.

It is a junction number, because it is equal to n+sod(n) for n = 687094 and 687103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687121) by changing a digit.

687128 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3200 + ... + 3407.

It is an arithmetic number, because the mean of its divisors is an integer number (86730).

2⁶⁸⁷¹²⁸ is an apocalyptic number.

It is an amenable number.

687128 is an abundant number, since it is smaller than the sum of its proper divisors (700552).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

687128 is a wasteful number, since it uses less digits than its factorization.

687128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6626 (or 6622 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 687128 is about 828.9318427953. The cubic root of 687128 is about 88.2427868496.

The spelling of 687128 in words is "six hundred eighty-seven thousand, one hundred twenty-eight".