1263768561 has 40 divisors (see below), whose sum is σ = 2064035424. Its totient is φ = 764225280.

The previous prime is 1263768553. The next prime is 1263768589. The reversal of 1263768561 is 1658673621.

1263768561 is a `hidden beast` number, since 1 + 2 + 637 + 6 + 8 + 5 + 6 + 1 = 666.

It is not a de Polignac number, because 1263768561 - 2³ = 1263768553 is a prime.

It is a super-2 number, since 2×1263768561² = 3194221951544021442, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1263768521) 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 in 39 ways as a sum of consecutive naturals, for example, 486081 + ... + 488673.

Almost surely, 2^1263768561 is an apocalyptic number.

1263768561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1263768561 is a deficient number, since it is larger than the sum of its proper divisors (800266863).

1263768561 is a wasteful number, since it uses less digits than its factorization.

1263768561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3163 (or 3154 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 1263768561 is about 35549.5226550231. The cubic root of 1263768561 is about 1081.1580402440.

The spelling of 1263768561 in words is "one billion, two hundred sixty-three million, seven hundred sixty-eight thousand, five hundred sixty-one".