266009921 has 2 divisors, whose sum is σ = 266009922. Its totient is φ = 266009920.

The previous prime is 266009917. The next prime is 266009923. The reversal of 266009921 is 129900662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 264225025 + 1784896 = 16255^2 + 1336^2 .

It is a cyclic number.

It is not a de Polignac number, because 266009921 - 2² = 266009917 is a prime.

It is a super-2 number, since 2×266009921² = 141522556140852482, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 266009923, 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 (266009923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133004960 + 133004961.

It is an arithmetic number, because the mean of its divisors is an integer number (133004961).

Almost surely, 2^266009921 is an apocalyptic number.

It is an amenable number.

266009921 is a deficient number, since it is larger than the sum of its proper divisors (1).

266009921 is an equidigital number, since it uses as much as digits as its factorization.

266009921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 266009921 is about 16309.8105752335. The cubic root of 266009921 is about 643.1307545535.

The spelling of 266009921 in words is "two hundred sixty-six million, nine thousand, nine hundred twenty-one".