208720913 has 2 divisors, whose sum is σ = 208720914. Its totient is φ = 208720912.

The previous prime is 208720907. The next prime is 208720921. The reversal of 208720913 is 319027802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135652609 + 73068304 = 11647^2 + 8548^2 .

It is a cyclic number.

It is not a de Polignac number, because 208720913 - 2⁸ = 208720657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 208720913.

It is not a weakly prime, because it can be changed into another prime (208720933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104360456 + 104360457.

It is an arithmetic number, because the mean of its divisors is an integer number (104360457).

Almost surely, 2^208720913 is an apocalyptic number.

It is an amenable number.

208720913 is a deficient number, since it is larger than the sum of its proper divisors (1).

208720913 is an equidigital number, since it uses as much as digits as its factorization.

208720913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 208720913 is about 14447.1766445905. The cubic root of 208720913 is about 593.1829442174.

The spelling of 208720913 in words is "two hundred eight million, seven hundred twenty thousand, nine hundred thirteen".