1291261087 has 2 divisors, whose sum is σ = 1291261088. Its totient is φ = 1291261086.

The previous prime is 1291261067. The next prime is 1291261091. The reversal of 1291261087 is 7801621921.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1291261087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291261007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645630543 + 645630544.

It is an arithmetic number, because the mean of its divisors is an integer number (645630544).

Almost surely, 2^1291261087 is an apocalyptic number.

1291261087 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291261087 is an equidigital number, since it uses as much as digits as its factorization.

1291261087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 1291261087 is about 35934.1214864090. The cubic root of 1291261087 is about 1088.9418474339.

The spelling of 1291261087 in words is "one billion, two hundred ninety-one million, two hundred sixty-one thousand, eighty-seven".