684621 has 12 divisors (see below), whose sum is σ = 1130272. Its totient is φ = 391176.

The previous prime is 684617. The next prime is 684637. The reversal of 684621 is 126486.

684621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 684621 - 2² = 684617 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684121) 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, 5371 + ... + 5496.

2⁶⁸⁴⁶²¹ is an apocalyptic number.

It is an amenable number.

684621 is a deficient number, since it is larger than the sum of its proper divisors (445651).

684621 is a wasteful number, since it uses less digits than its factorization.

684621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10880 (or 10877 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 684621 is about 827.4182739099. The cubic root of 684621 is about 88.1353375530.

The spelling of 684621 in words is "six hundred eighty-four thousand, six hundred twenty-one".