1263661549 has 2 divisors, whose sum is σ = 1263661550. Its totient is φ = 1263661548.

The previous prime is 1263661513. The next prime is 1263661589. The reversal of 1263661549 is 9451663621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1221502500 + 42159049 = 34950^2 + 6493^2 .

It is a cyclic number.

It is not a de Polignac number, because 1263661549 - 2¹⁵ = 1263628781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1263661589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631830774 + 631830775.

It is an arithmetic number, because the mean of its divisors is an integer number (631830775).

Almost surely, 2^1263661549 is an apocalyptic number.

It is an amenable number.

1263661549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1263661549 is an equidigital number, since it uses as much as digits as its factorization.

1263661549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 233280, while the sum is 43.

The square root of 1263661549 is about 35548.0175115294. The cubic root of 1263661549 is about 1081.1275230133.

The spelling of 1263661549 in words is "one billion, two hundred sixty-three million, six hundred sixty-one thousand, five hundred forty-nine".