209488381 has 2 divisors, whose sum is σ = 209488382. Its totient is φ = 209488380.

The previous prime is 209488379. The next prime is 209488403. The reversal of 209488381 is 183884902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 184036356 + 25452025 = 13566^2 + 5045^2 .

It is a cyclic number.

It is not a de Polignac number, because 209488381 - 2¹ = 209488379 is a prime.

It is a super-3 number, since 3×209488381³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 209488379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209488351) 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, 104744190 + 104744191.

It is an arithmetic number, because the mean of its divisors is an integer number (104744191).

Almost surely, 2^209488381 is an apocalyptic number.

It is an amenable number.

209488381 is a deficient number, since it is larger than the sum of its proper divisors (1).

209488381 is an equidigital number, since it uses as much as digits as its factorization.

209488381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 110592, while the sum is 43.

The square root of 209488381 is about 14473.7134488700. The cubic root of 209488381 is about 593.9091006177.

The spelling of 209488381 in words is "two hundred nine million, four hundred eighty-eight thousand, three hundred eighty-one".