684649 has 8 divisors (see below), whose sum is σ = 799488. Its totient is φ = 574080.

The previous prime is 684647. The next prime is 684683. The reversal of 684649 is 946486.

684649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 684649 - 2¹ = 684647 is a prime.

It is an Ulam number.

It is a d-powerful number, because it can be written as 6⁶ + 8⁵ + 6⁷ + 4⁶ + 4⁹ + 9⁵ .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 712 + ... + 1369.

It is an arithmetic number, because the mean of its divisors is an integer number (99936).

2⁶⁸⁴⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

684649 is a deficient number, since it is larger than the sum of its proper divisors (114839).

684649 is a wasteful number, since it uses less digits than its factorization.

684649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2135.

The product of its digits is 41472, while the sum is 37.

The square root of 684649 is about 827.4351938370. The cubic root of 684649 is about 88.1365390721.

The spelling of 684649 in words is "six hundred eighty-four thousand, six hundred forty-nine".