266343838515721 has 2 divisors, whose sum is σ = 266343838515722. Its totient is φ = 266343838515720.

The previous prime is 266343838515653. The next prime is 266343838515737. The reversal of 266343838515721 is 127515838343662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 266030322510096 + 313516005625 = 16310436^2 + 559925^2 .

It is a cyclic number.

It is not a de Polignac number, because 266343838515721 - 2²³ = 266343830127113 is a prime.

It is not a weakly prime, because it can be changed into another prime (266343838515761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133171919257860 + 133171919257861.

It is an arithmetic number, because the mean of its divisors is an integer number (133171919257861).

Almost surely, 2^{266343838515721} is an apocalyptic number.

It is an amenable number.

266343838515721 is a deficient number, since it is larger than the sum of its proper divisors (1).

266343838515721 is an equidigital number, since it uses as much as digits as its factorization.

266343838515721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 174182400, while the sum is 64.

The spelling of 266343838515721 in words is "two hundred sixty-six trillion, three hundred forty-three billion, eight hundred thirty-eight million, five hundred fifteen thousand, seven hundred twenty-one".