686969 has 2 divisors, whose sum is σ = 686970. Its totient is φ = 686968.

The previous prime is 686963. The next prime is 686971. The reversal of 686969 is 969686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 619369 + 67600 = 787^2 + 260^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686969 is a prime.

It is a super-2 number, since 2×686969² = 943852813922, which contains 22 as substring.

Together with 686971, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686963) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343484 + 343485.

It is an arithmetic number, because the mean of its divisors is an integer number (343485).

2⁶⁸⁶⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

686969 is a deficient number, since it is larger than the sum of its proper divisors (1).

686969 is an equidigital number, since it uses as much as digits as its factorization.

686969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 44.

The square root of 686969 is about 828.8359306883. The cubic root of 686969 is about 88.2359799250.

The spelling of 686969 in words is "six hundred eighty-six thousand, nine hundred sixty-nine".