266635261 has 2 divisors, whose sum is σ = 266635262. Its totient is φ = 266635260.

The previous prime is 266635231. The next prime is 266635273. The reversal of 266635261 is 162536662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 243547236 + 23088025 = 15606^2 + 4805^2 .

It is a cyclic number.

It is not a de Polignac number, because 266635261 - 2¹⁹ = 266110973 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 266635261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (266635231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133317630 + 133317631.

It is an arithmetic number, because the mean of its divisors is an integer number (133317631).

Almost surely, 2^266635261 is an apocalyptic number.

It is an amenable number.

266635261 is a deficient number, since it is larger than the sum of its proper divisors (1).

266635261 is an equidigital number, since it uses as much as digits as its factorization.

266635261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 37.

The square root of 266635261 is about 16328.9699920111. The cubic root of 266635261 is about 643.6343205469.

The spelling of 266635261 in words is "two hundred sixty-six million, six hundred thirty-five thousand, two hundred sixty-one".