1261513091 has 2 divisors, whose sum is σ = 1261513092. Its totient is φ = 1261513090.

The previous prime is 1261513087. The next prime is 1261513093. The reversal of 1261513091 is 1903151621.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1261513091 - 2² = 1261513087 is a prime.

It is a Sophie Germain prime.

Together with 1261513093, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1261513093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630756545 + 630756546.

It is an arithmetic number, because the mean of its divisors is an integer number (630756546).

Almost surely, 2^1261513091 is an apocalyptic number.

1261513091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261513091 is an equidigital number, since it uses as much as digits as its factorization.

1261513091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 1261513091 is about 35517.7855587873. The cubic root of 1261513091 is about 1080.5144699653.

The spelling of 1261513091 in words is "one billion, two hundred sixty-one million, five hundred thirteen thousand, ninety-one".