686771 has 4 divisors (see below), whose sum is σ = 690000. Its totient is φ = 683544.

The previous prime is 686761. The next prime is 686773. The reversal of 686771 is 177686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 177686 = 2 ⋅88843.

It is a cyclic number.

It is not a de Polignac number, because 686771 - 2¹⁰ = 685747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686773) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1271 + ... + 1728.

It is an arithmetic number, because the mean of its divisors is an integer number (172500).

2⁶⁸⁶⁷⁷¹ is an apocalyptic number.

686771 is a deficient number, since it is larger than the sum of its proper divisors (3229).

686771 is a wasteful number, since it uses less digits than its factorization.

686771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3228.

The product of its digits is 14112, while the sum is 35.

The square root of 686771 is about 828.7164774517. The cubic root of 686771 is about 88.2275019088.

It can be divided in two parts, 686 and 771, that multiplied together give a triangular number (528906 = T₁₀₂₈).

The spelling of 686771 in words is "six hundred eighty-six thousand, seven hundred seventy-one".