684816 has 40 divisors (see below), whose sum is σ = 1931424. Its totient is φ = 207360.

The previous prime is 684809. The next prime is 684829. The reversal of 684816 is 618486.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a nude number because it is divisible by every one of its digits.

It is a nialpdrome in base 16.

It is an unprimeable number.

684816 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 7 ways as a sum of consecutive naturals, for example, 121 + ... + 1176.

684816 is a Friedman number, since it can be written as 88*(6+6^(4+1)), using all its digits and the basic arithmetic operations.

2⁶⁸⁴⁸¹⁶ is an apocalyptic number.

684816 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 684816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (965712).

684816 is an abundant number, since it is smaller than the sum of its proper divisors (1246608).

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

684816 is a wasteful number, since it uses less digits than its factorization.

684816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1319 (or 1313 counting only the distinct ones).

The product of its digits is 9216, while the sum is 33.

The square root of 684816 is about 827.5361019315. The cubic root of 684816 is about 88.1437045956.

It can be divided in two parts, 68 and 4816, that added together give a palindrome (4884).

The spelling of 684816 in words is "six hundred eighty-four thousand, eight hundred sixteen".