686461 has 4 divisors (see below), whose sum is σ = 705052. Its totient is φ = 667872.

The previous prime is 686453. The next prime is 686473. The reversal of 686461 is 164686.

686461 = T₅₁ + T₅₂ + ... + T₁₆₁.

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

It can be written as a sum of positive squares in 2 ways, for example, as 319225 + 367236 = 565^2 + 606^2 .

It is a cyclic number.

It is not a de Polignac number, because 686461 - 2³ = 686453 is a prime.

It is a Duffinian number.

686461 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686761) 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, 9240 + ... + 9313.

It is an arithmetic number, because the mean of its divisors is an integer number (176263).

2⁶⁸⁶⁴⁶¹ is an apocalyptic number.

It is an amenable number.

686461 is a deficient number, since it is larger than the sum of its proper divisors (18591).

686461 is a wasteful number, since it uses less digits than its factorization.

686461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18590.

The product of its digits is 6912, while the sum is 31.

The square root of 686461 is about 828.5294201174. The cubic root of 686461 is about 88.2142249738.

The spelling of 686461 in words is "six hundred eighty-six thousand, four hundred sixty-one".