871681 has 2 divisors, whose sum is σ = 871682. Its totient is φ = 871680.

The previous prime is 871679. The next prime is 871687. The reversal of 871681 is 186178.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 846400 + 25281 = 920^2 + 159^2 .

It is a cyclic number.

It is not a de Polignac number, because 871681 - 2¹ = 871679 is a prime.

It is a super-2 number, since 2×871681² = 1519655531522, which contains 22 as substring.

Together with 871679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (871687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 435840 + 435841.

It is an arithmetic number, because the mean of its divisors is an integer number (435841).

2⁸⁷¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

871681 is a deficient number, since it is larger than the sum of its proper divisors (1).

871681 is an equidigital number, since it uses as much as digits as its factorization.

871681 is an evil number, because the sum of its binary digits is even.

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

The square root of 871681 is about 933.6385810366. The cubic root of 871681 is about 95.5254722218.

The spelling of 871681 in words is "eight hundred seventy-one thousand, six hundred eighty-one".