129871817 has 2 divisors, whose sum is σ = 129871818. Its totient is φ = 129871816.

The previous prime is 129871811. The next prime is 129871829. The reversal of 129871817 is 718178921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85729081 + 44142736 = 9259^2 + 6644^2 .

It is an emirp because it is prime and its reverse (718178921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 129871817 - 2⁸ = 129871561 is a prime.

It is not a weakly prime, because it can be changed into another prime (129871811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64935908 + 64935909.

It is an arithmetic number, because the mean of its divisors is an integer number (64935909).

Almost surely, 2^129871817 is an apocalyptic number.

It is an amenable number.

129871817 is a deficient number, since it is larger than the sum of its proper divisors (1).

129871817 is an equidigital number, since it uses as much as digits as its factorization.

129871817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56448, while the sum is 44.

The square root of 129871817 is about 11396.1316682460. The cubic root of 129871817 is about 506.4131473971.

The spelling of 129871817 in words is "one hundred twenty-nine million, eight hundred seventy-one thousand, eight hundred seventeen".