85991999 has 4 divisors (see below), whose sum is σ = 87821664. Its totient is φ = 84162336.

The previous prime is 85991993. The next prime is 85992007. The reversal of 85991999 is 99919958.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 85991999 - 2⁸ = 85991743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85991993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 914762 + ... + 914855.

It is an arithmetic number, because the mean of its divisors is an integer number (21955416).

Almost surely, 2^85991999 is an apocalyptic number.

85991999 is a deficient number, since it is larger than the sum of its proper divisors (1829665).

85991999 is a wasteful number, since it uses less digits than its factorization.

85991999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829664.

The product of its digits is 2361960, while the sum is 59.

The square root of 85991999 is about 9273.1871004526. The cubic root of 85991999 is about 441.3868072717.

The spelling of 85991999 in words is "eighty-five million, nine hundred ninety-one thousand, nine hundred ninety-nine".