688940 has 72 divisors (see below), whose sum is σ = 1819440. Its totient is φ = 217728.

The previous prime is 688939. The next prime is 688951. The reversal of 688940 is 49886.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 688940.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18602 + ... + 18638.

It is an arithmetic number, because the mean of its divisors is an integer number (25270).

2⁶⁸⁸⁹⁴⁰ 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 688940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (909720).

688940 is an abundant number, since it is smaller than the sum of its proper divisors (1130500).

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

688940 is a wasteful number, since it uses less digits than its factorization.

688940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 688940 is about 830.0240960358. The cubic root of 688940 is about 88.3202860362.

The spelling of 688940 in words is "six hundred eighty-eight thousand, nine hundred forty".