99999871 has 4 divisors (see below), whose sum is σ = 100020744. Its totient is φ = 99979000.

The previous prime is 99999847. The next prime is 99999931. The reversal of 99999871 is 17899999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17899999 = 13 ⋅1376923.

It is a cyclic number.

It is not a de Polignac number, because 99999871 - 2⁵ = 99999839 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 741 + ... + 14161.

It is an arithmetic number, because the mean of its divisors is an integer number (25005186).

Almost surely, 2^99999871 is an apocalyptic number.

99999871 is a deficient number, since it is larger than the sum of its proper divisors (20873).

99999871 is a wasteful number, since it uses less digits than its factorization.

99999871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20872.

The product of its digits is 3306744, while the sum is 61.

The square root of 99999871 is about 9999.9935499979. The cubic root of 99999871 is about 464.1586837729.

The spelling of 99999871 in words is "ninety-nine million, nine hundred ninety-nine thousand, eight hundred seventy-one".