871981 has 8 divisors (see below), whose sum is σ = 1007424. Its totient is φ = 745920.

The previous prime is 871973. The next prime is 871987. The reversal of 871981 is 189178.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 871981 - 2³ = 871973 is a prime.

It is a super-2 number, since 2×871981² = 1520701728722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (871987) 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 7 ways as a sum of consecutive naturals, for example, 2145 + ... + 2518.

It is an arithmetic number, because the mean of its divisors is an integer number (125928).

2⁸⁷¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

871981 is a deficient number, since it is larger than the sum of its proper divisors (135443).

871981 is a wasteful number, since it uses less digits than its factorization.

871981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4691.

The product of its digits is 4032, while the sum is 34.

The square root of 871981 is about 933.7992289566. The cubic root of 871981 is about 95.5364297298.

The spelling of 871981 in words is "eight hundred seventy-one thousand, nine hundred eighty-one".