681771 has 4 divisors (see below), whose sum is σ = 909032. Its totient is φ = 454512.

The previous prime is 681763. The next prime is 681773. The reversal of 681771 is 177186.

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

It is not a de Polignac number, because 681771 - 2³ = 681763 is a prime.

It is a D-number.

It is a Duffinian number.

681771 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (681773) 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 in 3 ways as a sum of consecutive naturals, for example, 113626 + ... + 113631.

It is an arithmetic number, because the mean of its divisors is an integer number (227258).

2⁶⁸¹⁷⁷¹ is an apocalyptic number.

681771 is a deficient number, since it is larger than the sum of its proper divisors (227261).

681771 is a wasteful number, since it uses less digits than its factorization.

681771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227260.

The product of its digits is 2352, while the sum is 30.

The square root of 681771 is about 825.6942533408. The cubic root of 681771 is about 88.0128682972.

The spelling of 681771 in words is "six hundred eighty-one thousand, seven hundred seventy-one".