208561973 has 2 divisors, whose sum is σ = 208561974. Its totient is φ = 208561972.

The previous prime is 208561937. The next prime is 208561981. The reversal of 208561973 is 379165802.

Together with previous prime (208561937) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 174187204 + 34374769 = 13198^2 + 5863^2 .

It is a cyclic number.

It is not a de Polignac number, because 208561973 - 2⁶ = 208561909 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 208561973.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208567973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104280986 + 104280987.

It is an arithmetic number, because the mean of its divisors is an integer number (104280987).

Almost surely, 2^208561973 is an apocalyptic number.

It is an amenable number.

208561973 is a deficient number, since it is larger than the sum of its proper divisors (1).

208561973 is an equidigital number, since it uses as much as digits as its factorization.

208561973 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 41.

The square root of 208561973 is about 14441.6748682416. The cubic root of 208561973 is about 593.0323373019.

The spelling of 208561973 in words is "two hundred eight million, five hundred sixty-one thousand, nine hundred seventy-three".