208640129 has 2 divisors, whose sum is σ = 208640130. Its totient is φ = 208640128.

The previous prime is 208640111. The next prime is 208640143. The reversal of 208640129 is 921046802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 208080625 + 559504 = 14425^2 + 748^2 .

It is a cyclic number.

It is not a de Polignac number, because 208640129 - 2¹² = 208636033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 208640095 and 208640104.

It is not a weakly prime, because it can be changed into another prime (208643129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104320064 + 104320065.

It is an arithmetic number, because the mean of its divisors is an integer number (104320065).

Almost surely, 2^208640129 is an apocalyptic number.

It is an amenable number.

208640129 is a deficient number, since it is larger than the sum of its proper divisors (1).

208640129 is an equidigital number, since it uses as much as digits as its factorization.

208640129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 208640129 is about 14444.3805336193. The cubic root of 208640129 is about 593.1064052098.

The spelling of 208640129 in words is "two hundred eight million, six hundred forty thousand, one hundred twenty-nine".