7666422221 has 4 divisors (see below), whose sum is σ = 8117388252. Its totient is φ = 7215456192.

The previous prime is 7666422199. The next prime is 7666422229. The reversal of 7666422221 is 1222246667.

It is a happy number.

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 5683501321 + 1982920900 = 75389^2 + 44530^2 .

It is a cyclic number.

It is not a de Polignac number, because 7666422221 - 2¹⁸ = 7666160077 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7666422229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225482990 + ... + 225483023.

It is an arithmetic number, because the mean of its divisors is an integer number (2029347063).

Almost surely, 2^7666422221 is an apocalyptic number.

It is an amenable number.

7666422221 is a deficient number, since it is larger than the sum of its proper divisors (450966031).

7666422221 is a wasteful number, since it uses less digits than its factorization.

7666422221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450966030.

The product of its digits is 96768, while the sum is 38.

The square root of 7666422221 is about 87558.1076828411. The cubic root of 7666422221 is about 1971.8062762881.

Adding to 7666422221 its reverse (1222246667), we get a palindrome (8888668888).

The spelling of 7666422221 in words is "seven billion, six hundred sixty-six million, four hundred twenty-two thousand, two hundred twenty-one".