100091 has 4 divisors (see below), whose sum is σ = 101184. Its totient is φ = 99000.

The previous prime is 100069. The next prime is 100103. The reversal of 100091 is 190001.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 190001 = 7 ⋅27143.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100291) 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, 395 + ... + 596.

It is an arithmetic number, because the mean of its divisors is an integer number (25296).

2¹⁰⁰⁰⁹¹ is an apocalyptic number.

100091 is a deficient number, since it is larger than the sum of its proper divisors (1093).

100091 is an equidigital number, since it uses as much as digits as its factorization.

100091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1092.

The product of its (nonzero) digits is 9, while the sum is 11.

The square root of 100091 is about 316.3716169317. The cubic root of 100091 is about 46.4299635536.

Adding to 100091 its reverse (190001), we get a palindrome (290092).

The spelling of 100091 in words is "one hundred thousand, ninety-one".