686626 has 4 divisors (see below), whose sum is σ = 1029942. Its totient is φ = 343312.

The previous prime is 686611. The next prime is 686639. The reversal of 686626 is 626686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 626686 = 2 ⋅313343.

It can be written as a sum of positive squares in only one way, i.e., 488601 + 198025 = 699^2 + 445^2 .

It is a plaindrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 686591 and 686600.

It is a congruent number.

It is an unprimeable number.

686626 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171655 + ... + 171658.

2⁶⁸⁶⁶²⁶ is an apocalyptic number.

686626 is a deficient number, since it is larger than the sum of its proper divisors (343316).

686626 is a wasteful number, since it uses less digits than its factorization.

686626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343315.

The product of its digits is 20736, while the sum is 34.

The square root of 686626 is about 828.6289881485. The cubic root of 686626 is about 88.2212922270.

The spelling of 686626 in words is "six hundred eighty-six thousand, six hundred twenty-six".