66021 has 8 divisors (see below), whose sum is σ = 89760. Its totient is φ = 43152.

The previous prime is 65993. The next prime is 66029. The reversal of 66021 is 12066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66021 - 2⁶ = 65957 is a prime.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66029) 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 7 ways as a sum of consecutive naturals, for example, 10 + ... + 363.

It is an arithmetic number, because the mean of its divisors is an integer number (11220).

2⁶⁶⁰²¹ is an apocalyptic number.

It is an amenable number.

66021 is a deficient number, since it is larger than the sum of its proper divisors (23739).

66021 is a wasteful number, since it uses less digits than its factorization.

66021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 66021 is about 256.9455195173. The cubic root of 66021 is about 40.4166859154.

Adding to 66021 its reverse (12066), we get a palindrome (78087).

The spelling of 66021 in words is "sixty-six thousand, twenty-one".