15881 has 2 divisors, whose sum is σ = 15882.
Its totient is φ = 15880.
The previous prime is 15877. The next prime is 15887. The reversal of 15881 is 18851.
15881 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 15625 + 256 = 125^2 + 16^2
It is a cyclic number.
It is not a de Polignac number, because 15881 - 22 = 15877 is a prime.
It is a super-2 number, since 2×158812 = 504412322, which contains 22 as substring.
It is a Chen prime.
It is an Ulam number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 15881.
It is not a weakly prime, because it can be changed into another prime (15887) 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 as a sum of consecutive naturals, namely, 7940 + 7941.
It is an arithmetic number, because the mean of its divisors is an integer number (7941).
215881 is an apocalyptic number.
It is an amenable number.
15881 is a deficient number, since it is larger than the sum of its proper divisors (1).
15881 is an equidigital number, since it uses as much as digits as its factorization.
15881 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 320, while the sum is 23.
The square root of 15881 is about 126.0198397079.
The cubic root of 15881 is about 25.1357943931.
The spelling of 15881 in words is "fifteen thousand, eight hundred eighty-one".