1311999979 has 2 divisors, whose sum is σ = 1311999980. Its totient is φ = 1311999978.

The previous prime is 1311999967. The next prime is 1312000003. The reversal of 1311999979 is 9799991131.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1311999979 - 2⁷ = 1311999851 is a prime.

It is not a weakly prime, because it can be changed into another prime (1311999919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655999989 + 655999990.

It is an arithmetic number, because the mean of its divisors is an integer number (655999990).

Almost surely, 2^1311999979 is an apocalyptic number.

1311999979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311999979 is an equidigital number, since it uses as much as digits as its factorization.

1311999979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1240029, while the sum is 58.

The square root of 1311999979 is about 36221.5402626669. The cubic root of 1311999979 is about 1094.7407291188.

The spelling of 1311999979 in words is "one billion, three hundred eleven million, nine hundred ninety-nine thousand, nine hundred seventy-nine".