129538781 has 2 divisors, whose sum is σ = 129538782. Its totient is φ = 129538780.

The previous prime is 129538777. The next prime is 129538811. The reversal of 129538781 is 187835921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95374756 + 34164025 = 9766^2 + 5845^2 .

It is a cyclic number.

It is not a de Polignac number, because 129538781 - 2² = 129538777 is a prime.

It is a super-2 number, since 2×129538781² = 33560591565931922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129538741) 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, 64769390 + 64769391.

It is an arithmetic number, because the mean of its divisors is an integer number (64769391).

Almost surely, 2^129538781 is an apocalyptic number.

It is an amenable number.

129538781 is a deficient number, since it is larger than the sum of its proper divisors (1).

129538781 is an equidigital number, since it uses as much as digits as its factorization.

129538781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 44.

The square root of 129538781 is about 11381.5104885072. The cubic root of 129538781 is about 505.9799043715.

The spelling of 129538781 in words is "one hundred twenty-nine million, five hundred thirty-eight thousand, seven hundred eighty-one".