266248721 has 2 divisors, whose sum is σ = 266248722. Its totient is φ = 266248720.

The previous prime is 266248709. The next prime is 266248753. The reversal of 266248721 is 127842662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 261792400 + 4456321 = 16180^2 + 2111^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-266248721 is a prime.

It is not a weakly prime, because it can be changed into another prime (266248771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133124360 + 133124361.

It is an arithmetic number, because the mean of its divisors is an integer number (133124361).

Almost surely, 2^266248721 is an apocalyptic number.

It is an amenable number.

266248721 is a deficient number, since it is larger than the sum of its proper divisors (1).

266248721 is an equidigital number, since it uses as much as digits as its factorization.

266248721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 38.

The square root of 266248721 is about 16317.1296801858. The cubic root of 266248721 is about 643.3231454861.

The spelling of 266248721 in words is "two hundred sixty-six million, two hundred forty-eight thousand, seven hundred twenty-one".