681439 has 4 divisors (see below), whose sum is σ = 743400. Its totient is φ = 619480.

The previous prime is 681427. The next prime is 681449. The reversal of 681439 is 934186.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 681439 - 2⁵ = 681407 is a prime.

It is a super-2 number, since 2×681439² = 928718221442, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 681439.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30964 + ... + 30985.

It is an arithmetic number, because the mean of its divisors is an integer number (185850).

2⁶⁸¹⁴³⁹ is an apocalyptic number.

681439 is a deficient number, since it is larger than the sum of its proper divisors (61961).

681439 is a wasteful number, since it uses less digits than its factorization.

681439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61960.

The product of its digits is 5184, while the sum is 31.

The square root of 681439 is about 825.4931859198. The cubic root of 681439 is about 87.9985795225.

The spelling of 681439 in words is "six hundred eighty-one thousand, four hundred thirty-nine".