51785 has 4 divisors (see below), whose sum is σ = 62148. Its totient is φ = 41424.

The previous prime is 51769. The next prime is 51787. The reversal of 51785 is 58715.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58715 = 5 ⋅11743.

It can be written as a sum of positive squares in 2 ways, for example, as 22201 + 29584 = 149^2 + 172^2 .

It is a cyclic number.

It is not a de Polignac number, because 51785 - 2⁴ = 51769 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51787) 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 in 3 ways as a sum of consecutive naturals, for example, 5174 + ... + 5183.

It is an arithmetic number, because the mean of its divisors is an integer number (15537).

2⁵¹⁷⁸⁵ is an apocalyptic number.

It is an amenable number.

51785 is a deficient number, since it is larger than the sum of its proper divisors (10363).

51785 is a wasteful number, since it uses less digits than its factorization.

51785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10362.

The product of its digits is 1400, while the sum is 26.

The square root of 51785 is about 227.5631780407. The cubic root of 51785 is about 37.2735988475.

The spelling of 51785 in words is "fifty-one thousand, seven hundred eighty-five".