684540 has 36 divisors (see below), whose sum is σ = 2076984. Its totient is φ = 182496.

The previous prime is 684527. The next prime is 684547. The reversal of 684540 is 45486.

684540 = T₃₆₅ + T₃₆₆ + ... + T₃₇₄.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684547) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1722 + ... + 2081.

It is an arithmetic number, because the mean of its divisors is an integer number (57694).

2⁶⁸⁴⁵⁴⁰ is an apocalyptic number.

684540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

684540 is an abundant number, since it is smaller than the sum of its proper divisors (1392444).

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

684540 is a wasteful number, since it uses less digits than its factorization.

684540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3818 (or 3813 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 684540 is about 827.3693250296. The cubic root of 684540 is about 88.1318615451.

The spelling of 684540 in words is "six hundred eighty-four thousand, five hundred forty".