100191 has 16 divisors (see below), whose sum is σ = 164864. Its totient is φ = 52704.

The previous prime is 100189. The next prime is 100193. The reversal of 100191 is 191001.

100191 = 78² + 79² + ... + 91².

It is an interprime number because it is at equal distance from previous prime (100189) and next prime (100193).

It is not a de Polignac number, because 100191 - 2¹ = 100189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100193) 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 15 ways as a sum of consecutive naturals, for example, 90 + ... + 456.

It is an arithmetic number, because the mean of its divisors is an integer number (10304).

2¹⁰⁰¹⁹¹ is an apocalyptic number.

100191 is a deficient number, since it is larger than the sum of its proper divisors (64673).

100191 is a wasteful number, since it uses less digits than its factorization.

100191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390.

The product of its (nonzero) digits is 9, while the sum is 12.

The square root of 100191 is about 316.5296194671. The cubic root of 100191 is about 46.4454209906.

Adding to 100191 its reverse (191001), we get a palindrome (291192).

The spelling of 100191 in words is "one hundred thousand, one hundred ninety-one".