129931381 has 2 divisors, whose sum is σ = 129931382. Its totient is φ = 129931380.

The previous prime is 129931297. The next prime is 129931387. The reversal of 129931381 is 183139921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129276900 + 654481 = 11370^2 + 809^2 .

It is an emirp because it is prime and its reverse (183139921) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129931381 is a prime.

It is a super-2 number, since 2×129931381² = 33764327537134322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 129931381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129931387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64965690 + 64965691.

It is an arithmetic number, because the mean of its divisors is an integer number (64965691).

Almost surely, 2^129931381 is an apocalyptic number.

It is an amenable number.

129931381 is a deficient number, since it is larger than the sum of its proper divisors (1).

129931381 is an equidigital number, since it uses as much as digits as its factorization.

129931381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 37.

The square root of 129931381 is about 11398.7447115900. The cubic root of 129931381 is about 506.4905554731.

The spelling of 129931381 in words is "one hundred twenty-nine million, nine hundred thirty-one thousand, three hundred eighty-one".