86991951 has 4 divisors (see below), whose sum is σ = 115989272. Its totient is φ = 57994632.

The previous prime is 86991913. The next prime is 86991977. The reversal of 86991951 is 15919968.

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

It is not a de Polignac number, because 86991951 - 2⁹ = 86991439 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 86991951.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86990951) 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, 14498656 + ... + 14498661.

It is an arithmetic number, because the mean of its divisors is an integer number (28997318).

Almost surely, 2^86991951 is an apocalyptic number.

86991951 is a deficient number, since it is larger than the sum of its proper divisors (28997321).

86991951 is a wasteful number, since it uses less digits than its factorization.

86991951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28997320.

The product of its digits is 174960, while the sum is 48.

The square root of 86991951 is about 9326.9475714191. The cubic root of 86991951 is about 443.0910968045.

The spelling of 86991951 in words is "eighty-six million, nine hundred ninety-one thousand, nine hundred fifty-one".