266972821 has 2 divisors, whose sum is σ = 266972822. Its totient is φ = 266972820.

The previous prime is 266972791. The next prime is 266972833. The reversal of 266972821 is 128279662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 181872196 + 85100625 = 13486^2 + 9225^2 .

It is a cyclic number.

It is not a de Polignac number, because 266972821 - 2⁵ = 266972789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (266972921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133486410 + 133486411.

It is an arithmetic number, because the mean of its divisors is an integer number (133486411).

Almost surely, 2^266972821 is an apocalyptic number.

It is an amenable number.

266972821 is a deficient number, since it is larger than the sum of its proper divisors (1).

266972821 is an equidigital number, since it uses as much as digits as its factorization.

266972821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 43.

The square root of 266972821 is about 16339.3029533086. The cubic root of 266972821 is about 643.9058194965.

The spelling of 266972821 in words is "two hundred sixty-six million, nine hundred seventy-two thousand, eight hundred twenty-one".