684478 has 4 divisors (see below), whose sum is σ = 1026720. Its totient is φ = 342238.

The previous prime is 684473. The next prime is 684493. The reversal of 684478 is 874486.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 874486 = 2 ⋅437243.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171118 + ... + 171121.

It is an arithmetic number, because the mean of its divisors is an integer number (256680).

2⁶⁸⁴⁴⁷⁸ is an apocalyptic number.

684478 is a deficient number, since it is larger than the sum of its proper divisors (342242).

684478 is a wasteful number, since it uses less digits than its factorization.

684478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342241.

The product of its digits is 43008, while the sum is 37.

The square root of 684478 is about 827.3318560288. The cubic root of 684478 is about 88.1292007119.

The spelling of 684478 in words is "six hundred eighty-four thousand, four hundred seventy-eight".