209902123 has 2 divisors, whose sum is σ = 209902124. Its totient is φ = 209902122.

The previous prime is 209902061. The next prime is 209902129. The reversal of 209902123 is 321209902.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209902123 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 209902091 and 209902100.

It is not a weakly prime, because it can be changed into another prime (209902129) 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, 104951061 + 104951062.

It is an arithmetic number, because the mean of its divisors is an integer number (104951062).

Almost surely, 2^209902123 is an apocalyptic number.

209902123 is a deficient number, since it is larger than the sum of its proper divisors (1).

209902123 is an equidigital number, since it uses as much as digits as its factorization.

209902123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 209902123 is about 14487.9992752623. Note that the first 3 decimals coincide. The cubic root of 209902123 is about 594.2998359657.

The spelling of 209902123 in words is "two hundred nine million, nine hundred two thousand, one hundred twenty-three".