666666242261 has 2 divisors, whose sum is σ = 666666242262. Its totient is φ = 666666242260.

The previous prime is 666666242201. The next prime is 666666242293. The reversal of 666666242261 is 162242666666.

666666242261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 511788575236 + 154877667025 = 715394^2 + 393545^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666666242261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666666242201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333333121130 + 333333121131.

It is an arithmetic number, because the mean of its divisors is an integer number (333333121131).

Almost surely, 2^666666242261 is an apocalyptic number.

It is an amenable number.

666666242261 is a deficient number, since it is larger than the sum of its proper divisors (1).

666666242261 is an equidigital number, since it uses as much as digits as its factorization.

666666242261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8957952, while the sum is 53.

The spelling of 666666242261 in words is "six hundred sixty-six billion, six hundred sixty-six million, two hundred forty-two thousand, two hundred sixty-one".