86991871 has 2 divisors, whose sum is σ = 86991872. Its totient is φ = 86991870.

The previous prime is 86991869. The next prime is 86991913. The reversal of 86991871 is 17819968.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 86991871 - 2¹ = 86991869 is a prime.

Together with 86991869, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (86991811) 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 as a sum of consecutive naturals, namely, 43495935 + 43495936.

It is an arithmetic number, because the mean of its divisors is an integer number (43495936).

Almost surely, 2^86991871 is an apocalyptic number.

86991871 is a deficient number, since it is larger than the sum of its proper divisors (1).

86991871 is an equidigital number, since it uses as much as digits as its factorization.

86991871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 49.

The square root of 86991871 is about 9326.9432827695. The cubic root of 86991871 is about 443.0909609785.

The spelling of 86991871 in words is "eighty-six million, nine hundred ninety-one thousand, eight hundred seventy-one".