266219861 has 2 divisors, whose sum is σ = 266219862. Its totient is φ = 266219860.

The previous prime is 266219851. The next prime is 266219867. The reversal of 266219861 is 168912662.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 185776900 + 80442961 = 13630^2 + 8969^2 .

It is a cyclic number.

It is not a de Polignac number, because 266219861 - 2¹⁰ = 266218837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (266219867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133109930 + 133109931.

It is an arithmetic number, because the mean of its divisors is an integer number (133109931).

Almost surely, 2^266219861 is an apocalyptic number.

It is an amenable number.

266219861 is a deficient number, since it is larger than the sum of its proper divisors (1).

266219861 is an equidigital number, since it uses as much as digits as its factorization.

266219861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 41.

The square root of 266219861 is about 16316.2453095067. The cubic root of 266219861 is about 643.2999003330.

The spelling of 266219861 in words is "two hundred sixty-six million, two hundred nineteen thousand, eight hundred sixty-one".