871861 has 4 divisors (see below), whose sum is σ = 909792. Its totient is φ = 833932.

The previous prime is 871837. The next prime is 871867. The reversal of 871861 is 168178.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 168178 = 2 ⋅84089.

It is a cyclic number.

It is not a de Polignac number, because 871861 - 2⁹ = 871349 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a pancake number, because a pancake can be divided into 871861 parts by 1320 straight cuts.

It is a Duffinian number.

871861 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (871867) 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, 18931 + ... + 18976.

It is an arithmetic number, because the mean of its divisors is an integer number (227448).

2⁸⁷¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

871861 is a deficient number, since it is larger than the sum of its proper divisors (37931).

871861 is a wasteful number, since it uses less digits than its factorization.

871861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37930.

The product of its digits is 2688, while the sum is 31.

The square root of 871861 is about 933.7349731053. The cubic root of 871861 is about 95.5320470282.

The spelling of 871861 in words is "eight hundred seventy-one thousand, eight hundred sixty-one".