265806221 has 2 divisors, whose sum is σ = 265806222. Its totient is φ = 265806220.

The previous prime is 265806209. The next prime is 265806223. The reversal of 265806221 is 122608562.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 225420196 + 40386025 = 15014^2 + 6355^2 .

It is a cyclic number.

It is not a de Polignac number, because 265806221 - 2¹⁸ = 265544077 is a prime.

It is a Sophie Germain prime.

Together with 265806223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (265806223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132903110 + 132903111.

It is an arithmetic number, because the mean of its divisors is an integer number (132903111).

Almost surely, 2^265806221 is an apocalyptic number.

It is an amenable number.

265806221 is a deficient number, since it is larger than the sum of its proper divisors (1).

265806221 is an equidigital number, since it uses as much as digits as its factorization.

265806221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 265806221 is about 16303.5646715680. The cubic root of 265806221 is about 642.9665511682.

The spelling of 265806221 in words is "two hundred sixty-five million, eight hundred six thousand, two hundred twenty-one".