684890 has 8 divisors (see below), whose sum is σ = 1232820. Its totient is φ = 273952.

The previous prime is 684889. The next prime is 684923. The reversal of 684890 is 98486.

It can be written as a sum of positive squares in 2 ways, for example, as 683929 + 961 = 827^2 + 31^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 684890.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34235 + ... + 34254.

2⁶⁸⁴⁸⁹⁰ is an apocalyptic number.

684890 is a deficient number, since it is larger than the sum of its proper divisors (547930).

684890 is a wasteful number, since it uses less digits than its factorization.

684890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68496.

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

The square root of 684890 is about 827.5808117640. The cubic root of 684890 is about 88.1468793653.

It can be divided in two parts, 68 and 4890, that multiplied together give a triangular number (332520 = T₈₁₅).

The spelling of 684890 in words is "six hundred eighty-four thousand, eight hundred ninety".