51845 has 4 divisors (see below), whose sum is σ = 62220. Its totient is φ = 41472.

The previous prime is 51839. The next prime is 51853. The reversal of 51845 is 54815.

51845 is nontrivially palindromic in base 13.

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 9409 + 42436 = 97^2 + 206^2 .

It is a cyclic number.

It is not a de Polignac number, because 51845 - 2⁴ = 51829 is a prime.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 51845.

It is a congruent number.

It is an unprimeable number.

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, 5180 + ... + 5189.

It is an arithmetic number, because the mean of its divisors is an integer number (15555).

2⁵¹⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

51845 is a deficient number, since it is larger than the sum of its proper divisors (10375).

51845 is a wasteful number, since it uses less digits than its factorization.

51845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10374.

The product of its digits is 800, while the sum is 23.

The square root of 51845 is about 227.6949713981. The cubic root of 51845 is about 37.2879888109.

The spelling of 51845 in words is "fifty-one thousand, eight hundred forty-five".