15911 has 4 divisors (see below), whose sum is σ = 18192. Its totient is φ = 13632.

The previous prime is 15907. The next prime is 15913. The reversal of 15911 is 11951.

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 15911 - 2² = 15907 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 15911.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1130 + ... + 1143.

It is an arithmetic number, because the mean of its divisors is an integer number (4548).

2¹⁵⁹¹¹ is an apocalyptic number.

15911 is a deficient number, since it is larger than the sum of its proper divisors (2281).

15911 is an equidigital number, since it uses as much as digits as its factorization.

15911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2280.

The product of its digits is 45, while the sum is 17.

The square root of 15911 is about 126.1388124250. The cubic root of 15911 is about 25.1516120264.

The spelling of 15911 in words is "fifteen thousand, nine hundred eleven".