209890469 has 2 divisors, whose sum is σ = 209890470. Its totient is φ = 209890468.

The previous prime is 209890463. The next prime is 209890481. The reversal of 209890469 is 964098902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 165508225 + 44382244 = 12865^2 + 6662^2 .

It is a cyclic number.

It is not a de Polignac number, because 209890469 - 2¹² = 209886373 is a prime.

It is a super-2 number, since 2×209890469² = 88108017954079922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209890463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104945234 + 104945235.

It is an arithmetic number, because the mean of its divisors is an integer number (104945235).

Almost surely, 2^209890469 is an apocalyptic number.

It is an amenable number.

209890469 is a deficient number, since it is larger than the sum of its proper divisors (1).

209890469 is an equidigital number, since it uses as much as digits as its factorization.

209890469 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 47.

The square root of 209890469 is about 14487.5970747395. The cubic root of 209890469 is about 594.2888370322.

The spelling of 209890469 in words is "two hundred nine million, eight hundred ninety thousand, four hundred sixty-nine".