57991 has 2 divisors, whose sum is σ = 57992. Its totient is φ = 57990.
The previous prime is 57977. The next prime is 58013. The reversal of 57991 is 19975.
57991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a weak prime.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-57991 is a prime.
It is a zygodrome in base 3.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (57901) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28995 + 28996.
It is an arithmetic number, because the mean of its divisors is an integer number (28996).
257991 is an apocalyptic number.
57991 is a deficient number, since it is larger than the sum of its proper divisors (1).
57991 is an equidigital number, since it uses as much as digits as its factorization.
57991 is an evil number, because the sum of its binary digits is even.
The product of its digits is 2835, while the sum is 31.
The square root of 57991 is about 240.8132056180. The cubic root of 57991 is about 38.7067641251.
The spelling of 57991 in words is "fifty-seven thousand, nine hundred ninety-one".
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