51664 has 10 divisors (see below), whose sum is σ = 100130. Its totient is φ = 25824.

The previous prime is 51659. The next prime is 51673. The reversal of 51664 is 46615.

It can be written as a sum of positive squares in only one way, i.e., 40000 + 11664 = 200^2 + 108^2 .

It is a nialpdrome in base 9.

It is a congruent number.

It is an unprimeable number.

51664 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 as a sum of consecutive naturals, namely, 1599 + ... + 1630.

It is an arithmetic number, because the mean of its divisors is an integer number (10013).

2⁵¹⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

51664 is a deficient number, since it is larger than the sum of its proper divisors (48466).

51664 is a wasteful number, since it uses less digits than its factorization.

51664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3237 (or 3231 counting only the distinct ones).

The product of its digits is 720, while the sum is 22.

The square root of 51664 is about 227.2971623228. The cubic root of 51664 is about 37.2445452427.

The spelling of 51664 in words is "fifty-one thousand, six hundred sixty-four".