1291316779 has 4 divisors (see below), whose sum is σ = 1359280840. Its totient is φ = 1223352720.

The previous prime is 1291316777. The next prime is 1291316791. The reversal of 1291316779 is 9776131921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9776131921 = 19 ⋅514533259.

It is a cyclic number.

It is not a de Polignac number, because 1291316779 - 2¹ = 1291316777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291316777) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33982002 + ... + 33982039.

It is an arithmetic number, because the mean of its divisors is an integer number (339820210).

Almost surely, 2^1291316779 is an apocalyptic number.

1291316779 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1291316779 is a deficient number, since it is larger than the sum of its proper divisors (67964061).

1291316779 is an equidigital number, since it uses as much as digits as its factorization.

1291316779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67964060.

The product of its digits is 142884, while the sum is 46.

The square root of 1291316779 is about 35934.8963961217. The cubic root of 1291316779 is about 1088.9575025373.

It can be divided in two parts, 12913 and 16779, that added together give a palindrome (29692).

The spelling of 1291316779 in words is "one billion, two hundred ninety-one million, three hundred sixteen thousand, seven hundred seventy-nine".