8550666721 has 4 divisors (see below), whose sum is σ = 8626336452. Its totient is φ = 8474996992.

The previous prime is 8550666679. The next prime is 8550666743. The reversal of 8550666721 is 1276660558.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2847396321 + 5703270400 = 53361^2 + 75520^2 .

It is a cyclic number.

It is not a de Polignac number, because 8550666721 - 2¹⁷ = 8550535649 is a prime.

It is a super-2 number, since 2×8550666721² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8550666781) 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 3 ways as a sum of consecutive naturals, for example, 37834696 + ... + 37834921.

It is an arithmetic number, because the mean of its divisors is an integer number (2156584113).

Almost surely, 2^8550666721 is an apocalyptic number.

It is an amenable number.

8550666721 is a deficient number, since it is larger than the sum of its proper divisors (75669731).

8550666721 is a wasteful number, since it uses less digits than its factorization.

8550666721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75669730.

The product of its (nonzero) digits is 604800, while the sum is 46.

The square root of 8550666721 is about 92469.8151885252. The cubic root of 8550666721 is about 2044.8745025339.

The spelling of 8550666721 in words is "eight billion, five hundred fifty million, six hundred sixty-six thousand, seven hundred twenty-one".