66888221 has 8 divisors (see below), whose sum is σ = 67985280. Its totient is φ = 65796192.

The previous prime is 66888197. The next prime is 66888223. The reversal of 66888221 is 12288866.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66888221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66888223) 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, 32810 + ... + 34788.

It is an arithmetic number, because the mean of its divisors is an integer number (8498160).

Almost surely, 2^66888221 is an apocalyptic number.

It is an amenable number.

66888221 is a deficient number, since it is larger than the sum of its proper divisors (1097059).

66888221 is a wasteful number, since it uses less digits than its factorization.

66888221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2515.

The product of its digits is 73728, while the sum is 41.

The square root of 66888221 is about 8178.5219324766. The cubic root of 66888221 is about 405.9288157694.

The spelling of 66888221 in words is "sixty-six million, eight hundred eighty-eight thousand, two hundred twenty-one".