1267999391 has 2 divisors, whose sum is σ = 1267999392. Its totient is φ = 1267999390.

The previous prime is 1267999373. The next prime is 1267999429. The reversal of 1267999391 is 1939997621.

It is a weak prime.

It is an emirp because it is prime and its reverse (1939997621) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1267999391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1267999091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633999695 + 633999696.

It is an arithmetic number, because the mean of its divisors is an integer number (633999696).

Almost surely, 2^1267999391 is an apocalyptic number.

1267999391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1267999391 is an equidigital number, since it uses as much as digits as its factorization.

1267999391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1653372, while the sum is 56.

The square root of 1267999391 is about 35608.9790783167. The cubic root of 1267999391 is about 1082.3631925703.

The spelling of 1267999391 in words is "one billion, two hundred sixty-seven million, nine hundred ninety-nine thousand, three hundred ninety-one".