1261565507 has 2 divisors, whose sum is σ = 1261565508. Its totient is φ = 1261565506.

The previous prime is 1261565497. The next prime is 1261565581. The reversal of 1261565507 is 7055651621.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1261565507 - 2⁶ = 1261565443 is a prime.

It is not a weakly prime, because it can be changed into another prime (1261562507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630782753 + 630782754.

It is an arithmetic number, because the mean of its divisors is an integer number (630782754).

Almost surely, 2^1261565507 is an apocalyptic number.

1261565507 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261565507 is an equidigital number, since it uses as much as digits as its factorization.

1261565507 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 63000, while the sum is 38.

The square root of 1261565507 is about 35518.5234349628. The cubic root of 1261565507 is about 1080.5294349209.

The spelling of 1261565507 in words is "one billion, two hundred sixty-one million, five hundred sixty-five thousand, five hundred seven".