684645 has 16 divisors (see below), whose sum is σ = 1180032. Its totient is φ = 336960.

The previous prime is 684643. The next prime is 684647. The reversal of 684645 is 546486.

It is a happy number.

684645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (684643) and next prime (684647).

It is a Wieferich number.

It is not a de Polignac number, because 684645 - 2¹ = 684643 is a prime.

It is a congruent 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 15 ways as a sum of consecutive naturals, for example, 1561 + ... + 1950.

It is an arithmetic number, because the mean of its divisors is an integer number (73752).

2⁶⁸⁴⁶⁴⁵ is an apocalyptic number.

684645 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

684645 is a deficient number, since it is larger than the sum of its proper divisors (495387).

684645 is a wasteful number, since it uses less digits than its factorization.

684645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3532.

The product of its digits is 23040, while the sum is 33.

The square root of 684645 is about 827.4327767257. The cubic root of 684645 is about 88.1363674286.

The spelling of 684645 in words is "six hundred eighty-four thousand, six hundred forty-five".