1386317981 has 2 divisors, whose sum is σ = 1386317982. Its totient is φ = 1386317980.

The previous prime is 1386317963. The next prime is 1386317983. The reversal of 1386317981 is 1897136831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1292402500 + 93915481 = 35950^2 + 9691^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1386317981 is a prime.

It is a super-2 number, since 2×1386317981² = 3843755088887832722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1386317983, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1386317983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693158990 + 693158991.

It is an arithmetic number, because the mean of its divisors is an integer number (693158991).

Almost surely, 2^1386317981 is an apocalyptic number.

It is an amenable number.

1386317981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1386317981 is an equidigital number, since it uses as much as digits as its factorization.

1386317981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 47.

The square root of 1386317981 is about 37233.2912995883. The cubic root of 1386317981 is about 1115.0327380844.

The spelling of 1386317981 in words is "one billion, three hundred eighty-six million, three hundred seventeen thousand, nine hundred eighty-one".