6666645861121 has 4 divisors (see below), whose sum is σ = 6666979864644. Its totient is φ = 6666311857600.

The previous prime is 6666645861101. The next prime is 6666645861137. The reversal of 6666645861121 is 1211685466666.

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 6237201558721 + 429444302400 = 2497439^2 + 655320^2 .

It is a cyclic number.

It is not a de Polignac number, because 6666645861121 - 2¹⁷ = 6666645730049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6666645861101) 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, 166971820 + ... + 167011741.

It is an arithmetic number, because the mean of its divisors is an integer number (1666744966161).

Almost surely, 2^{6666645861121} is an apocalyptic number.

It is an amenable number.

6666645861121 is a deficient number, since it is larger than the sum of its proper divisors (334003523).

6666645861121 is a wasteful number, since it uses less digits than its factorization.

6666645861121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334003522.

The product of its digits is 14929920, while the sum is 58.

The spelling of 6666645861121 in words is "six trillion, six hundred sixty-six billion, six hundred forty-five million, eight hundred sixty-one thousand, one hundred twenty-one".