871661 has 6 divisors (see below), whose sum is σ = 1014030. Its totient is φ = 747096.

The previous prime is 871657. The next prime is 871679. The reversal of 871661 is 166178.

It can be written as a sum of positive squares in only one way, i.e., 866761 + 4900 = 931^2 + 70^2 .

It is not a de Polignac number, because 871661 - 2² = 871657 is a prime.

It is a super-3 number, since 3×871661³ = 1986845514199133343, which contains 333 as substring.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 871661.

It is not an unprimeable number, because it can be changed into a prime (871621) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8846 + ... + 8943.

It is an arithmetic number, because the mean of its divisors is an integer number (169005).

2⁸⁷¹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

871661 is a deficient number, since it is larger than the sum of its proper divisors (142369).

871661 is a wasteful number, since it uses less digits than its factorization.

871661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17803 (or 17796 counting only the distinct ones).

The product of its digits is 2016, while the sum is 29.

The square root of 871661 is about 933.6278701924. The cubic root of 871661 is about 95.5247416319.

The spelling of 871661 in words is "eight hundred seventy-one thousand, six hundred sixty-one".