266664440407021 has 2 divisors, whose sum is σ = 266664440407022. Its totient is φ = 266664440407020.

The previous prime is 266664440407007. The next prime is 266664440407121. The reversal of 266664440407021 is 120704044466662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 250802302154121 + 15862138252900 = 15836739^2 + 3982730^2 .

It is a cyclic number.

It is not a de Polignac number, because 266664440407021 - 2¹⁹ = 266664439882733 is a prime.

It is a super-2 number, since 2×266664440407021² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 266664440407021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (266664440407121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133332220203510 + 133332220203511.

It is an arithmetic number, because the mean of its divisors is an integer number (133332220203511).

Almost surely, 2^{266664440407021} is an apocalyptic number.

It is an amenable number.

266664440407021 is a deficient number, since it is larger than the sum of its proper divisors (1).

266664440407021 is an equidigital number, since it uses as much as digits as its factorization.

266664440407021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9289728, while the sum is 52.

The spelling of 266664440407021 in words is "two hundred sixty-six trillion, six hundred sixty-four billion, four hundred forty million, four hundred seven thousand, twenty-one".