86819991 has 4 divisors (see below), whose sum is σ = 115759992. Its totient is φ = 57879992.

The previous prime is 86819927. The next prime is 86820011. The reversal of 86819991 is 19991868.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 86819991 - 2⁶ = 86819927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86819791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14469996 + ... + 14470001.

It is an arithmetic number, because the mean of its divisors is an integer number (28939998).

Almost surely, 2^86819991 is an apocalyptic number.

86819991 is a deficient number, since it is larger than the sum of its proper divisors (28940001).

86819991 is a wasteful number, since it uses less digits than its factorization.

86819991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28940000.

The product of its digits is 279936, while the sum is 51.

The square root of 86819991 is about 9317.7245612864. The cubic root of 86819991 is about 442.7989463837.

The spelling of 86819991 in words is "eighty-six million, eight hundred nineteen thousand, nine hundred ninety-one".