51808 has 12 divisors (see below), whose sum is σ = 102060. Its totient is φ = 25888.

The previous prime is 51803. The next prime is 51817. The reversal of 51808 is 80815.

51808 is nontrivially palindromic in base 5.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778 + ... + 841.

It is an arithmetic number, because the mean of its divisors is an integer number (8505).

2⁵¹⁸⁰⁸ is an apocalyptic number.

It is an amenable number.

51808 is a deficient number, since it is larger than the sum of its proper divisors (50252).

51808 is a wasteful number, since it uses less digits than its factorization.

51808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1629 (or 1621 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 51808 is about 227.6137078473. The cubic root of 51808 is about 37.2791163132.

The spelling of 51808 in words is "fifty-one thousand, eight hundred eight".