53666 has 4 divisors (see below), whose sum is σ = 80502. Its totient is φ = 26832.

The previous prime is 53657. The next prime is 53681. The reversal of 53666 is 66635.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66635 = 5 ⋅13327.

It can be written as a sum of positive squares in only one way, i.e., 52441 + 1225 = 229^2 + 35^2 .

It is an unprimeable number.

53666 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, 13415 + ... + 13418.

2⁵³⁶⁶⁶ is an apocalyptic number.

53666 is a deficient number, since it is larger than the sum of its proper divisors (26836).

53666 is a wasteful number, since it uses less digits than its factorization.

53666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26835.

The product of its digits is 3240, while the sum is 26.

The square root of 53666 is about 231.6592324946. The cubic root of 53666 is about 37.7195418251.

The spelling of 53666 in words is "fifty-three thousand, six hundred sixty-six".