85109891 has 12 divisors (see below), whose sum is σ = 88982040. Its totient is φ = 81357120.

The previous prime is 85109881. The next prime is 85109929. The reversal of 85109891 is 19890158.

It is a de Polignac number, because none of the positive numbers 2^k-85109891 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (85109831) 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 11 ways as a sum of consecutive naturals, for example, 114800 + ... + 115538.

It is an arithmetic number, because the mean of its divisors is an integer number (7415170).

Almost surely, 2^85109891 is an apocalyptic number.

85109891 is a deficient number, since it is larger than the sum of its proper divisors (3872149).

85109891 is an equidigital number, since it uses as much as digits as its factorization.

85109891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 886 (or 833 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 41.

The square root of 85109891 is about 9225.5022085521. The cubic root of 85109891 is about 439.8723648387.

The spelling of 85109891 in words is "eighty-five million, one hundred nine thousand, eight hundred ninety-one".