209669813 has 2 divisors, whose sum is σ = 209669814. Its totient is φ = 209669812.

The previous prime is 209669753. The next prime is 209669821. The reversal of 209669813 is 318966902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 176411524 + 33258289 = 13282^2 + 5767^2 .

It is a cyclic number.

It is not a de Polignac number, because 209669813 - 2¹⁶ = 209604277 is a prime.

It is a super-2 number, since 2×209669813² = 87922860966909938, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209669843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104834906 + 104834907.

It is an arithmetic number, because the mean of its divisors is an integer number (104834907).

Almost surely, 2^209669813 is an apocalyptic number.

It is an amenable number.

209669813 is a deficient number, since it is larger than the sum of its proper divisors (1).

209669813 is an equidigital number, since it uses as much as digits as its factorization.

209669813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 209669813 is about 14479.9797306488. The cubic root of 209669813 is about 594.0805071380.

The spelling of 209669813 in words is "two hundred nine million, six hundred sixty-nine thousand, eight hundred thirteen".