684840438 has 24 divisors (see below), whose sum is σ = 1484325648. Its totient is φ = 228202512.

The previous prime is 684840421. The next prime is 684840449. The reversal of 684840438 is 834048486.

It is a junction number, because it is equal to n+sod(n) for n = 684840393 and 684840402.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 77095 + ... + 85517.

It is an arithmetic number, because the mean of its divisors is an integer number (61846902).

Almost surely, 2^684840438 is an apocalyptic number.

684840438 is an abundant number, since it is smaller than the sum of its proper divisors (799485210).

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

684840438 is a wasteful number, since it uses less digits than its factorization.

684840438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12948 (or 12945 counting only the distinct ones).

The product of its (nonzero) digits is 589824, while the sum is 45.

The square root of 684840438 is about 26169.4562037502. The cubic root of 684840438 is about 881.4475306715.

The spelling of 684840438 in words is "six hundred eighty-four million, eight hundred forty thousand, four hundred thirty-eight".