129858821 has 2 divisors, whose sum is σ = 129858822. Its totient is φ = 129858820.

The previous prime is 129858803. The next prime is 129858829. The reversal of 129858821 is 128858921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90345025 + 39513796 = 9505^2 + 6286^2 .

It is an emirp because it is prime and its reverse (128858921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 129858821 - 2¹⁰ = 129857797 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 (129858829) 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, 64929410 + 64929411.

It is an arithmetic number, because the mean of its divisors is an integer number (64929411).

Almost surely, 2^129858821 is an apocalyptic number.

It is an amenable number.

129858821 is a deficient number, since it is larger than the sum of its proper divisors (1).

129858821 is an equidigital number, since it uses as much as digits as its factorization.

129858821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 92160, while the sum is 44.

The square root of 129858821 is about 11395.5614604986. The cubic root of 129858821 is about 506.3962549335.

The spelling of 129858821 in words is "one hundred twenty-nine million, eight hundred fifty-eight thousand, eight hundred twenty-one".