17891 has 2 divisors, whose sum is σ = 17892.
Its totient is φ = 17890.
The previous prime is 17881. The next prime is 17903. The reversal of 17891 is 19871.
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 17891 - 26 = 17827 is a prime.
It is a Chen prime.
It is a self number, because there is not a number n which added to its sum of digits gives 17891.
It is not a weakly prime, because it can be changed into another prime (17851) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8945 + 8946.
It is an arithmetic number, because the mean of its divisors is an integer number (8946).
217891 is an apocalyptic number.
17891 is a deficient number, since it is larger than the sum of its proper divisors (1).
17891 is an equidigital number, since it uses as much as digits as its factorization.
17891 is an evil number, because the sum of its binary digits is even.
The product of its digits is 504, while the sum is 26.
The square root of 17891 is about 133.7572427945.
The cubic root of 17891 is about 26.1544066511.
The spelling of 17891 in words is "seventeen thousand, eight hundred ninety-one".