51985 has 8 divisors (see below), whose sum is σ = 64296. Its totient is φ = 40320.

The previous prime is 51977. The next prime is 51991. The reversal of 51985 is 58915.

51985 is nontrivially palindromic in base 6.

It is a Cunningham number, because it is equal to 228²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 18496 + 33489 = 136^2 + 183^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51985 - 2³ = 51977 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

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 7 ways as a sum of consecutive naturals, for example, 45 + ... + 325.

It is an arithmetic number, because the mean of its divisors is an integer number (8037).

2⁵¹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

51985 is a deficient number, since it is larger than the sum of its proper divisors (12311).

51985 is a wasteful number, since it uses less digits than its factorization.

51985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323.

The product of its digits is 1800, while the sum is 28.

The square root of 51985 is about 228.0021929719. The cubic root of 51985 is about 37.3215222700.

The spelling of 51985 in words is "fifty-one thousand, nine hundred eighty-five".