31091 has 2 divisors, whose sum is σ = 31092.
Its totient is φ = 31090.
The previous prime is 31081. The next prime is 31121. The reversal of 31091 is 19013.
It is a weak prime.
It is an emirp because it is prime and its reverse (19013) is a distict prime.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-31091 is a prime.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31091.
It is not a weakly prime, because it can be changed into another prime (31051) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15545 + 15546.
It is an arithmetic number, because the mean of its divisors is an integer number (15546).
231091 is an apocalyptic number.
31091 is a deficient number, since it is larger than the sum of its proper divisors (1).
31091 is an equidigital number, since it uses as much as digits as its factorization.
31091 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 27, while the sum is 14.
The square root of 31091 is about 176.3264018801.
The cubic root of 31091 is about 31.4445147365.
Note that the first 3 decimals are identical.
The spelling of 31091 in words is "thirty-one thousand, ninety-one".