108019991 has 4 divisors (see below), whose sum is σ = 108129984. Its totient is φ = 107910000.

The previous prime is 108019957. The next prime is 108020021. The reversal of 108019991 is 199910801.

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 108019991 - 2¹⁸ = 107757847 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 (108019931) 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, 53510 + ... + 55491.

It is an arithmetic number, because the mean of its divisors is an integer number (27032496).

Almost surely, 2^108019991 is an apocalyptic number.

108019991 is a deficient number, since it is larger than the sum of its proper divisors (109993).

108019991 is an equidigital number, since it uses as much as digits as its factorization.

108019991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109992.

The product of its (nonzero) digits is 5832, while the sum is 38.

The square root of 108019991 is about 10393.2666183448. The cubic root of 108019991 is about 476.2496968651.

The spelling of 108019991 in words is "one hundred eight million, nineteen thousand, nine hundred ninety-one".