51791 has 4 divisors (see below), whose sum is σ = 52632.
Its totient is φ = 50952.
The previous prime is 51787. The next prime is 51797. The reversal of 51791 is 19715.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19715 = 5 ⋅3943.
It is a cyclic number.
It is not a de Polignac number, because 51791 - 22 = 51787 is a prime.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (51797) 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, 320 + ... + 453.
It is an arithmetic number, because the mean of its divisors is an integer number (13158).
251791 is an apocalyptic number.
51791 is a deficient number, since it is larger than the sum of its proper divisors (841).
51791 is an equidigital number, since it uses as much as digits as its factorization.
51791 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 840.
The product of its digits is 315, while the sum is 23.
The square root of 51791 is about 227.5763608110.
The cubic root of 51791 is about 37.2750383439.
The spelling of 51791 in words is "fifty-one thousand, seven hundred ninety-one".