51857 has 4 divisors (see below), whose sum is σ = 55860. Its totient is φ = 47856.

The previous prime is 51853. The next prime is 51859. The reversal of 51857 is 75815.

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 15376 + 36481 = 124^2 + 191^2 .

It is a cyclic number.

It is not a de Polignac number, because 51857 - 2² = 51853 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (51853) 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, 1982 + ... + 2007.

It is an arithmetic number, because the mean of its divisors is an integer number (13965).

2⁵¹⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

51857 is a deficient number, since it is larger than the sum of its proper divisors (4003).

51857 is a wasteful number, since it uses less digits than its factorization.

51857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4002.

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

The square root of 51857 is about 227.7213209166. The cubic root of 51857 is about 37.2908654711.

It can be divided in two parts, 518 and 57, that added together give a palindrome (575).

The spelling of 51857 in words is "fifty-one thousand, eight hundred fifty-seven".