684381 has 4 divisors (see below), whose sum is σ = 912512. Its totient is φ = 456252.

The previous prime is 684379. The next prime is 684407. The reversal of 684381 is 183486.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 684381 - 2¹ = 684379 is a prime.

It is a super-2 number, since 2×684381² = 936754706322, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114061 + ... + 114066.

It is an arithmetic number, because the mean of its divisors is an integer number (228128).

2⁶⁸⁴³⁸¹ is an apocalyptic number.

It is an amenable number.

684381 is a deficient number, since it is larger than the sum of its proper divisors (228131).

684381 is a wasteful number, since it uses less digits than its factorization.

684381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228130.

The product of its digits is 4608, while the sum is 30.

The square root of 684381 is about 827.2732317681. The cubic root of 684381 is about 88.1250374729.

The spelling of 684381 in words is "six hundred eighty-four thousand, three hundred eighty-one".