684895 has 4 divisors (see below), whose sum is σ = 821880. Its totient is φ = 547912.

The previous prime is 684889. The next prime is 684923. The reversal of 684895 is 598486.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 684895 - 2⁷ = 684767 is a prime.

It is a super-2 number, since 2×684895² = 938162322050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

684895 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68485 + ... + 68494.

It is an arithmetic number, because the mean of its divisors is an integer number (205470).

2⁶⁸⁴⁸⁹⁵ is an apocalyptic number.

684895 is a deficient number, since it is larger than the sum of its proper divisors (136985).

684895 is a wasteful number, since it uses less digits than its factorization.

684895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136984.

The product of its digits is 69120, while the sum is 40.

The square root of 684895 is about 827.5838326115. The cubic root of 684895 is about 88.1470938685.

The spelling of 684895 in words is "six hundred eighty-four thousand, eight hundred ninety-five".