686438 has 4 divisors (see below), whose sum is σ = 1029660. Its totient is φ = 343218.

The previous prime is 686437. The next prime is 686449. The reversal of 686438 is 834686.

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

It is a junction number, because it is equal to n+sod(n) for n = 686398 and 686407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686437) 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 as a sum of consecutive naturals, namely, 171608 + ... + 171611.

It is an arithmetic number, because the mean of its divisors is an integer number (257415).

2⁶⁸⁶⁴³⁸ is an apocalyptic number.

686438 is a deficient number, since it is larger than the sum of its proper divisors (343222).

686438 is a wasteful number, since it uses less digits than its factorization.

686438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343221.

The product of its digits is 27648, while the sum is 35.

The square root of 686438 is about 828.5155399870. The cubic root of 686438 is about 88.2132397516.

The spelling of 686438 in words is "six hundred eighty-six thousand, four hundred thirty-eight".