86978191 has 4 divisors (see below), whose sum is σ = 87301800. Its totient is φ = 86654584.

The previous prime is 86978189. The next prime is 86978197. The reversal of 86978191 is 19187968.

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

It is not a de Polignac number, because 86978191 - 2¹ = 86978189 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 (86978197) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161401 + ... + 161938.

It is an arithmetic number, because the mean of its divisors is an integer number (21825450).

Almost surely, 2^86978191 is an apocalyptic number.

86978191 is a deficient number, since it is larger than the sum of its proper divisors (323609).

86978191 is a wasteful number, since it uses less digits than its factorization.

86978191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323608.

The product of its digits is 217728, while the sum is 49.

The square root of 86978191 is about 9326.2098947000. The cubic root of 86978191 is about 443.0677335128.

The spelling of 86978191 in words is "eighty-six million, nine hundred seventy-eight thousand, one hundred ninety-one".