686761 has 2 divisors, whose sum is σ = 686762. Its totient is φ = 686760.

The previous prime is 686737. The next prime is 686773. The reversal of 686761 is 167686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 553536 + 133225 = 744^2 + 365^2 .

It is a cyclic number.

It is not a de Polignac number, because 686761 - 2⁵ = 686729 is a prime.

It is a super-2 number, since 2×686761² = 943281342242, which contains 22 as substring.

It is a nialpdrome in base 15.

It is not a weakly prime, because it can be changed into another prime (686731) 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, 343380 + 343381.

It is an arithmetic number, because the mean of its divisors is an integer number (343381).

2⁶⁸⁶⁷⁶¹ is an apocalyptic number.

It is an amenable number.

686761 is a deficient number, since it is larger than the sum of its proper divisors (1).

686761 is an equidigital number, since it uses as much as digits as its factorization.

686761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 34.

The square root of 686761 is about 828.7104440032. The cubic root of 686761 is about 88.2270736830.

The spelling of 686761 in words is "six hundred eighty-six thousand, seven hundred sixty-one".