209125129 has 2 divisors, whose sum is σ = 209125130. Its totient is φ = 209125128.

The previous prime is 209125069. The next prime is 209125159. The reversal of 209125129 is 921521902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115519504 + 93605625 = 10748^2 + 9675^2 .

It is a cyclic number.

It is not a de Polignac number, because 209125129 - 2¹⁵ = 209092361 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 209125129.

It is not a weakly prime, because it can be changed into another prime (209125159) 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, 104562564 + 104562565.

It is an arithmetic number, because the mean of its divisors is an integer number (104562565).

Almost surely, 2^209125129 is an apocalyptic number.

It is an amenable number.

209125129 is a deficient number, since it is larger than the sum of its proper divisors (1).

209125129 is an equidigital number, since it uses as much as digits as its factorization.

209125129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 209125129 is about 14461.1593242036. The cubic root of 209125129 is about 593.5656233573.

The spelling of 209125129 in words is "two hundred nine million, one hundred twenty-five thousand, one hundred twenty-nine".