51685 has 4 divisors (see below), whose sum is σ = 62028. Its totient is φ = 41344.

The previous prime is 51683. The next prime is 51691. The reversal of 51685 is 58615.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8836 + 42849 = 94^2 + 207^2 .

It is a cyclic number.

It is not a de Polignac number, because 51685 - 2¹ = 51683 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 (51683) 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, 5164 + ... + 5173.

It is an arithmetic number, because the mean of its divisors is an integer number (15507).

2⁵¹⁶⁸⁵ is an apocalyptic number.

It is an amenable number.

51685 is a deficient number, since it is larger than the sum of its proper divisors (10343).

51685 is a wasteful number, since it uses less digits than its factorization.

51685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10342.

The product of its digits is 1200, while the sum is 25.

The square root of 51685 is about 227.3433526629. The cubic root of 51685 is about 37.2495908548.

The spelling of 51685 in words is "fifty-one thousand, six hundred eighty-five".