83999991 has 8 divisors (see below), whose sum is σ = 112127104. Its totient is φ = 55936440.

The previous prime is 83999947. The next prime is 83999999. The reversal of 83999991 is 19999938.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 83999991 - 2⁹ = 83999479 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 (83999999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12715 + ... + 18156.

It is an arithmetic number, because the mean of its divisors is an integer number (14015888).

Almost surely, 2^83999991 is an apocalyptic number.

83999991 is a deficient number, since it is larger than the sum of its proper divisors (28127113).

83999991 is a wasteful number, since it uses less digits than its factorization.

83999991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31781.

The product of its digits is 1417176, while the sum is 57.

The square root of 83999991 is about 9165.1508989214. The cubic root of 83999991 is about 437.9518983476.

Adding to 83999991 its sum of digits (57), we get a palindrome (84000048).

The spelling of 83999991 in words is "eighty-three million, nine hundred ninety-nine thousand, nine hundred ninety-one".