51666 has 16 divisors (see below), whose sum is σ = 105600. Its totient is φ = 16848.

The previous prime is 51659. The next prime is 51673. The reversal of 51666 is 66615.

51666 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (51659) and next prime (51673).

It is a Curzon number.

It is a plaindrome in base 11.

It is a nialpdrome in base 9.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 51666.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 420 + ... + 528.

It is an arithmetic number, because the mean of its divisors is an integer number (6600).

2⁵¹⁶⁶⁶ is an apocalyptic number.

51666 is an abundant number, since it is smaller than the sum of its proper divisors (53934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52800).

51666 is a wasteful number, since it uses less digits than its factorization.

51666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193.

The product of its digits is 1080, while the sum is 24.

The square root of 51666 is about 227.3015618072. The cubic root of 51666 is about 37.2450258361.

It can be divided in two parts, 51 and 666, that added together give a palindrome (717).

The spelling of 51666 in words is "fifty-one thousand, six hundred sixty-six".