684640826 has 8 divisors (see below), whose sum is σ = 1032635604. Its totient is φ = 340428960.

The previous prime is 684640819. The next prime is 684640829. The reversal of 684640826 is 628046486.

684640826 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 561453025 + 123187801 = 23695^2 + 11099^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (684640829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 945275 + ... + 945998.

Almost surely, 2^684640826 is an apocalyptic number.

684640826 is a deficient number, since it is larger than the sum of its proper divisors (347994778).

684640826 is a wasteful number, since it uses less digits than its factorization.

684640826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1891456.

The product of its (nonzero) digits is 442368, while the sum is 44.

The square root of 684640826 is about 26165.6420903444. The cubic root of 684640826 is about 881.3618831775.

The spelling of 684640826 in words is "six hundred eighty-four million, six hundred forty thousand, eight hundred twenty-six".