687820 has 48 divisors (see below), whose sum is σ = 1753920. Its totient is φ = 221952.

The previous prime is 687809. The next prime is 687823. The reversal of 687820 is 28786.

It is not an unprimeable number, because it can be changed into a prime (687823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40452 + ... + 40468.

It is an arithmetic number, because the mean of its divisors is an integer number (36540).

2⁶⁸⁷⁸²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 687820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (876960).

687820 is an abundant number, since it is smaller than the sum of its proper divisors (1066100).

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

687820 is a wasteful number, since it uses less digits than its factorization.

687820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67 (or 31 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 687820 is about 829.3491424002. The cubic root of 687820 is about 88.2723997315.

The spelling of 687820 in words is "six hundred eighty-seven thousand, eight hundred twenty".