86191209 has 20 divisors (see below), whose sum is σ = 138660676. Its totient is φ = 53040096.

The previous prime is 86191181. The next prime is 86191211. The reversal of 86191209 is 90219168.

It can be written as a sum of positive squares in 2 ways, for example, as 47403225 + 38787984 = 6885^2 + 6228^2 .

It is not a de Polignac number, because 86191209 - 2⁵ = 86191177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (86191289) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 39874 + ... + 41979.

Almost surely, 2^86191209 is an apocalyptic number.

It is an amenable number.

86191209 is a deficient number, since it is larger than the sum of its proper divisors (52469467).

86191209 is a wasteful number, since it uses less digits than its factorization.

86191209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81878 (or 81869 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 86191209 is about 9283.9220699013. The cubic root of 86191209 is about 441.7273849042.

The spelling of 86191209 in words is "eighty-six million, one hundred ninety-one thousand, two hundred nine".