66621 has 8 divisors (see below), whose sum is σ = 90720. Its totient is φ = 43472.

The previous prime is 66617. The next prime is 66629. The reversal of 66621 is 12666.

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

It is a cyclic number.

It is not a de Polignac number, because 66621 - 2² = 66617 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66629) 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, 51 + ... + 368.

It is an arithmetic number, because the mean of its divisors is an integer number (11340).

2⁶⁶⁶²¹ is an apocalyptic number.

It is an amenable number.

66621 is a deficient number, since it is larger than the sum of its proper divisors (24099).

66621 is a wasteful number, since it uses less digits than its factorization.

66621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475.

The product of its digits is 432, while the sum is 21.

The square root of 66621 is about 258.1104414781. The cubic root of 66621 is about 40.5387527260.

The spelling of 66621 in words is "sixty-six thousand, six hundred twenty-one".