208509923 has 2 divisors, whose sum is σ = 208509924. Its totient is φ = 208509922.

The previous prime is 208509919. The next prime is 208510013. The reversal of 208509923 is 329905802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 208509923 - 2² = 208509919 is a prime.

It is not a weakly prime, because it can be changed into another prime (208509523) 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, 104254961 + 104254962.

It is an arithmetic number, because the mean of its divisors is an integer number (104254962).

Almost surely, 2^208509923 is an apocalyptic number.

208509923 is a deficient number, since it is larger than the sum of its proper divisors (1).

208509923 is an equidigital number, since it uses as much as digits as its factorization.

208509923 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 208509923 is about 14439.8726794941. The cubic root of 208509923 is about 592.9829996065.

The spelling of 208509923 in words is "two hundred eight million, five hundred nine thousand, nine hundred twenty-three".