684545 has 8 divisors (see below), whose sum is σ = 849960. Its totient is φ = 528640.

The previous prime is 684527. The next prime is 684547. The reversal of 684545 is 545486.

It can be written as a sum of positive squares in 4 ways, for example, as 82369 + 602176 = 287^2 + 776^2 .

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

It is not a de Polignac number, because 684545 - 2⁸ = 684289 is a prime.

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 pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2216 + ... + 2505.

It is an arithmetic number, because the mean of its divisors is an integer number (106245).

2⁶⁸⁴⁵⁴⁵ is an apocalyptic number.

It is an amenable number.

684545 is a deficient number, since it is larger than the sum of its proper divisors (165415).

684545 is a wasteful number, since it uses less digits than its factorization.

684545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4755.

The product of its digits is 19200, while the sum is 32.

The square root of 684545 is about 827.3723466493. The cubic root of 684545 is about 88.1320761214.

It can be divided in two parts, 6845 and 45, that multiplied together give a square (308025 = 555²).

The spelling of 684545 in words is "six hundred eighty-four thousand, five hundred forty-five".