266323721 has 2 divisors, whose sum is σ = 266323722. Its totient is φ = 266323720.

The previous prime is 266323691. The next prime is 266323723. The reversal of 266323721 is 127323662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 260467321 + 5856400 = 16139^2 + 2420^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-266323721 is a prime.

It is a Sophie Germain prime.

Together with 266323723, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (266323723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133161860 + 133161861.

It is an arithmetic number, because the mean of its divisors is an integer number (133161861).

Almost surely, 2^266323721 is an apocalyptic number.

It is an amenable number.

266323721 is a deficient number, since it is larger than the sum of its proper divisors (1).

266323721 is an equidigital number, since it uses as much as digits as its factorization.

266323721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 32.

The square root of 266323721 is about 16319.4277166817. The cubic root of 266323721 is about 643.3835460344.

The spelling of 266323721 in words is "two hundred sixty-six million, three hundred twenty-three thousand, seven hundred twenty-one".