1271002391 has 2 divisors, whose sum is σ = 1271002392. Its totient is φ = 1271002390.

The previous prime is 1271002373. The next prime is 1271002423. The reversal of 1271002391 is 1932001721.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1271002391 - 2²⁶ = 1203893527 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1271002391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1271002351) 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 as a sum of consecutive naturals, namely, 635501195 + 635501196.

It is an arithmetic number, because the mean of its divisors is an integer number (635501196).

Almost surely, 2^1271002391 is an apocalyptic number.

1271002391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1271002391 is an equidigital number, since it uses as much as digits as its factorization.

1271002391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 1271002391 is about 35651.1204732755. The cubic root of 1271002391 is about 1083.2169716650.

The spelling of 1271002391 in words is "one billion, two hundred seventy-one million, two thousand, three hundred ninety-one".