129427861 has 2 divisors, whose sum is σ = 129427862. Its totient is φ = 129427860.

The previous prime is 129427849. The next prime is 129427871. The reversal of 129427861 is 168724921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111703761 + 17724100 = 10569^2 + 4210^2 .

It is a cyclic number.

It is not a de Polignac number, because 129427861 - 2⁹ = 129427349 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129427811) 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, 64713930 + 64713931.

It is an arithmetic number, because the mean of its divisors is an integer number (64713931).

Almost surely, 2^129427861 is an apocalyptic number.

It is an amenable number.

129427861 is a deficient number, since it is larger than the sum of its proper divisors (1).

129427861 is an equidigital number, since it uses as much as digits as its factorization.

129427861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 40.

The square root of 129427861 is about 11376.6366295140. The cubic root of 129427861 is about 505.8354448847.

The spelling of 129427861 in words is "one hundred twenty-nine million, four hundred twenty-seven thousand, eight hundred sixty-one".