209921113 has 2 divisors, whose sum is σ = 209921114. Its totient is φ = 209921112.

The previous prime is 209921099. The next prime is 209921123. The reversal of 209921113 is 311129902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120297024 + 89624089 = 10968^2 + 9467^2 .

It is a cyclic number.

It is not a de Polignac number, because 209921113 - 2²¹ = 207823961 is a prime.

It is not a weakly prime, because it can be changed into another prime (209921123) 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, 104960556 + 104960557.

It is an arithmetic number, because the mean of its divisors is an integer number (104960557).

Almost surely, 2^209921113 is an apocalyptic number.

It is an amenable number.

209921113 is a deficient number, since it is larger than the sum of its proper divisors (1).

209921113 is an equidigital number, since it uses as much as digits as its factorization.

209921113 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 209921113 is about 14488.6546304341. The cubic root of 209921113 is about 594.3177576735.

The spelling of 209921113 in words is "two hundred nine million, nine hundred twenty-one thousand, one hundred thirteen".