66556652221 has 8 divisors (see below), whose sum is σ = 68373144504. Its totient is φ = 64749358080.

The previous prime is 66556652191. The next prime is 66556652233. The reversal of 66556652221 is 12225665566.

It can be written as a sum of positive squares in 4 ways, for example, as 319908996 + 66236743225 = 17886^2 + 257365^2 .

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 66556652221 - 2⁵ = 66556652189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66556652821) 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, 2284866 + ... + 2313811.

It is an arithmetic number, because the mean of its divisors is an integer number (8546643063).

Almost surely, 2^66556652221 is an apocalyptic number.

It is an amenable number.

66556652221 is a deficient number, since it is larger than the sum of its proper divisors (1816492283).

66556652221 is a wasteful number, since it uses less digits than its factorization.

66556652221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4599071.

The product of its digits is 1296000, while the sum is 46.

The spelling of 66556652221 in words is "sixty-six billion, five hundred fifty-six million, six hundred fifty-two thousand, two hundred twenty-one".