Search a number
4191 = 311127

4191 has 8 divisors (see below), whose sum is σ = 6144. Its totient is φ = 2520.

The previous prime is 4177. The next prime is 4201. The reversal of 4191 is 1914.

Added to its reverse (1914) it gives a triangular number (6105 = T110).

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

It is not a de Polignac number, because 4191 - 25 = 4159 is a prime.

It is a Smith number, since the sum of its digits (15) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 4191.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 4191.

It is not an unprimeable number, because it can be changed into a prime (4111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31 + ... + 96.

It is an arithmetic number, because the mean of its divisors is an integer number (768).

24191 is an apocalyptic number.

4191 is a deficient number, since it is larger than the sum of its proper divisors (1953).

4191 is a wasteful number, since it uses less digits than its factorization.

With its successor (4192) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (141).

4191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141.

The product of its digits is 36, while the sum is 15.

The square root of 4191 is about 64.7379332386. The cubic root of 4191 is about 16.1227537283.

Adding to 4191 its reverse (1914), we get a triangular number (6105 = T110).

The spelling of 4191 in words is "four thousand, one hundred ninety-one".

Divisors: 1 3 11 33 127 381 1397 4191