83991111 has 4 divisors (see below), whose sum is σ = 111988152. Its totient is φ = 55994072.

The previous prime is 83991107. The next prime is 83991119. The reversal of 83991111 is 11119938.

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 83991111 - 2² = 83991107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83991119) 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 3 ways as a sum of consecutive naturals, for example, 13998516 + ... + 13998521.

It is an arithmetic number, because the mean of its divisors is an integer number (27997038).

Almost surely, 2^83991111 is an apocalyptic number.

83991111 is a deficient number, since it is larger than the sum of its proper divisors (27997041).

83991111 is a wasteful number, since it uses less digits than its factorization.

83991111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27997040.

The product of its digits is 1944, while the sum is 33.

The square root of 83991111 is about 9164.6664423753. Note that the first 3 decimals coincide. The cubic root of 83991111 is about 437.9364652114.

The spelling of 83991111 in words is "eighty-three million, nine hundred ninety-one thousand, one hundred eleven".