6646912221 has 8 divisors (see below), whose sum is σ = 8894545504. Its totient is φ = 4415276880.

The previous prime is 6646912199. The next prime is 6646912243. The reversal of 6646912221 is 1222196466.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (6646912199) and next prime (6646912243).

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

It is not a de Polignac number, because 6646912221 - 2⁵ = 6646912189 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6646912221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6646912021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3998515 + ... + 4000176.

It is an arithmetic number, because the mean of its divisors is an integer number (1111818188).

Almost surely, 2^6646912221 is an apocalyptic number.

It is an amenable number.

6646912221 is a deficient number, since it is larger than the sum of its proper divisors (2247633283).

6646912221 is a wasteful number, since it uses less digits than its factorization.

6646912221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7998971.

The product of its digits is 62208, while the sum is 39.

The square root of 6646912221 is about 81528.5975655168. The cubic root of 6646912221 is about 1880.2112540824.

The spelling of 6646912221 in words is "six billion, six hundred forty-six million, nine hundred twelve thousand, two hundred twenty-one".