871858813 has 18 divisors (see below), whose sum is σ = 1050431226. Its totient is φ = 721504224.

The previous prime is 871858811. The next prime is 871858831. The reversal of 871858813 is 318858178.

It can be written as a sum of positive squares in 3 ways, for example, as 9966649 + 861892164 = 3157^2 + 29358^2 .

It is not a de Polignac number, because 871858813 - 2¹ = 871858811 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (871858811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 30631 + ... + 51787.

Almost surely, 2^871858813 is an apocalyptic number.

It is an amenable number.

871858813 is a deficient number, since it is larger than the sum of its proper divisors (178572413).

871858813 is a wasteful number, since it uses less digits than its factorization.

871858813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21229 (or 21193 counting only the distinct ones).

The product of its digits is 430080, while the sum is 49.

The square root of 871858813 is about 29527.2554261313. The cubic root of 871858813 is about 955.3196714978.

The spelling of 871858813 in words is "eight hundred seventy-one million, eight hundred fifty-eight thousand, eight hundred thirteen".