99999985 has 16 divisors (see below), whose sum is σ = 122601600. Its totient is φ = 78278656.

The previous prime is 99999971. The next prime is 99999989. The reversal of 99999985 is 58999999.

It is a cyclic number.

It is not a de Polignac number, because 99999985 - 2²⁵ = 66445553 is a prime.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 99999985.

It is not an unprimeable number, because it can be changed into a prime (99999989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75156 + ... + 76474.

It is an arithmetic number, because the mean of its divisors is an integer number (7662600).

Almost surely, 2^99999985 is an apocalyptic number.

It is an amenable number.

99999985 is a deficient number, since it is larger than the sum of its proper divisors (22601615).

99999985 is a wasteful number, since it uses less digits than its factorization.

99999985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1640.

The product of its digits is 21257640, while the sum is 67.

The square root of 99999985 is about 9999.9992500000. Note that the first 3 decimals coincide. The cubic root of 99999985 is about 464.1588601533.

The spelling of 99999985 in words is "ninety-nine million, nine hundred ninety-nine thousand, nine hundred eighty-five".