1311211987 has 2 divisors, whose sum is σ = 1311211988. Its totient is φ = 1311211986.

The previous prime is 1311211933. The next prime is 1311211999. The reversal of 1311211987 is 7891121131.

It is a strong prime.

It is an emirp because it is prime and its reverse (7891121131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1311211987 - 2⁷ = 1311211859 is a prime.

It is not a weakly prime, because it can be changed into another prime (1311211487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655605993 + 655605994.

It is an arithmetic number, because the mean of its divisors is an integer number (655605994).

Almost surely, 2^1311211987 is an apocalyptic number.

1311211987 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311211987 is an equidigital number, since it uses as much as digits as its factorization.

1311211987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 34.

The square root of 1311211987 is about 36210.6612339515. The cubic root of 1311211987 is about 1094.5215167939.

The spelling of 1311211987 in words is "one billion, three hundred eleven million, two hundred eleven thousand, nine hundred eighty-seven".