129986861 has 2 divisors, whose sum is σ = 129986862. Its totient is φ = 129986860.

The previous prime is 129986839. The next prime is 129986911. The reversal of 129986861 is 168689921.

It is a happy number.

It is an a-pointer prime, because the next prime (129986911) can be obtained adding 129986861 to its sum of digits (50).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125865961 + 4120900 = 11219^2 + 2030^2 .

It is a cyclic number.

It is not a de Polignac number, because 129986861 - 2¹⁰ = 129985837 is a prime.

It is a Sophie Germain prime.

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 (129986261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64993430 + 64993431.

It is an arithmetic number, because the mean of its divisors is an integer number (64993431).

Almost surely, 2^129986861 is an apocalyptic number.

It is an amenable number.

129986861 is a deficient number, since it is larger than the sum of its proper divisors (1).

129986861 is an equidigital number, since it uses as much as digits as its factorization.

129986861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 50.

The square root of 129986861 is about 11401.1780531663. The cubic root of 129986861 is about 506.5626347948.

The spelling of 129986861 in words is "one hundred twenty-nine million, nine hundred eighty-six thousand, eight hundred sixty-one".