66389 has 4 divisors (see below), whose sum is σ = 66924. Its totient is φ = 65856.

The previous prime is 66383. The next prime is 66403. The reversal of 66389 is 98366.

It is a happy number.

66389 is nontrivially palindromic in base 14.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 46225 + 20164 = 215^2 + 142^2 .

It is a cyclic number.

It is not a de Polignac number, because 66389 - 2⁴ = 66373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66383) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 29 + ... + 365.

It is an arithmetic number, because the mean of its divisors is an integer number (16731).

2⁶⁶³⁸⁹ is an apocalyptic number.

It is an amenable number.

66389 is a deficient number, since it is larger than the sum of its proper divisors (535).

66389 is a wasteful number, since it uses less digits than its factorization.

66389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534.

The product of its digits is 7776, while the sum is 32.

The square root of 66389 is about 257.6606295110. The cubic root of 66389 is about 40.4916408090.

The spelling of 66389 in words is "sixty-six thousand, three hundred eighty-nine".