3191318981 has 2 divisors, whose sum is σ = 3191318982. Its totient is φ = 3191318980.

The previous prime is 3191318971. The next prime is 3191318987. The reversal of 3191318981 is 1898131913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1620465025 + 1570853956 = 40255^2 + 39634^2 .

It is an emirp because it is prime and its reverse (1898131913) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3191318981 is a prime.

It is a super-4 number, since 4×3191318981⁴ (a number of 39 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3191318987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1595659490 + 1595659491.

It is an arithmetic number, because the mean of its divisors is an integer number (1595659491).

Almost surely, 2^3191318981 is an apocalyptic number.

It is an amenable number.

3191318981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3191318981 is an equidigital number, since it uses as much as digits as its factorization.

3191318981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 44.

The square root of 3191318981 is about 56491.7602929843. The cubic root of 3191318981 is about 1472.2788448402.

The spelling of 3191318981 in words is "three billion, one hundred ninety-one million, three hundred eighteen thousand, nine hundred eighty-one".