1266563549 has 2 divisors, whose sum is σ = 1266563550. Its totient is φ = 1266563548.

The previous prime is 1266563527. The next prime is 1266563633. The reversal of 1266563549 is 9453656621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1265224900 + 1338649 = 35570^2 + 1157^2 .

It is a cyclic number.

It is not a de Polignac number, because 1266563549 - 2²⁸ = 998128093 is a prime.

It is a Sophie Germain 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 (1266563509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633281774 + 633281775.

It is an arithmetic number, because the mean of its divisors is an integer number (633281775).

Almost surely, 2^1266563549 is an apocalyptic number.

It is an amenable number.

1266563549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266563549 is an equidigital number, since it uses as much as digits as its factorization.

1266563549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1166400, while the sum is 47.

The square root of 1266563549 is about 35588.8121324666. The cubic root of 1266563549 is about 1081.9544937657.

The spelling of 1266563549 in words is "one billion, two hundred sixty-six million, five hundred sixty-three thousand, five hundred forty-nine".