9871591 has 2 divisors, whose sum is σ = 9871592. Its totient is φ = 9871590.

The previous prime is 9871573. The next prime is 9871607. The reversal of 9871591 is 1951789.

It is a happy number.

9871591 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9871591 - 2¹⁵ = 9838823 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9871501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4935795 + 4935796.

It is an arithmetic number, because the mean of its divisors is an integer number (4935796).

Almost surely, 2^9871591 is an apocalyptic number.

9871591 is a deficient number, since it is larger than the sum of its proper divisors (1).

9871591 is an equidigital number, since it uses as much as digits as its factorization.

9871591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 40.

The square root of 9871591 is about 3141.9088147176. The cubic root of 9871591 is about 214.5173307884.

The spelling of 9871591 in words is "nine million, eight hundred seventy-one thousand, five hundred ninety-one".