66633621 has 8 divisors (see below), whose sum is σ = 89088384. Its totient is φ = 44300640.

The previous prime is 66633607. The next prime is 66633629. The reversal of 66633621 is 12633666.

It is a happy number.

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

It is not a de Polignac number, because 66633621 - 2¹¹ = 66631573 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66633629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29160 + ... + 31361.

It is an arithmetic number, because the mean of its divisors is an integer number (11136048).

Almost surely, 2^66633621 is an apocalyptic number.

It is an amenable number.

66633621 is a deficient number, since it is larger than the sum of its proper divisors (22454763).

66633621 is a wasteful number, since it uses less digits than its factorization.

66633621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60891.

The product of its digits is 23328, while the sum is 33.

The square root of 66633621 is about 8162.9419329063. The cubic root of 66633621 is about 405.4131251588.

The spelling of 66633621 in words is "sixty-six million, six hundred thirty-three thousand, six hundred twenty-one".