209489247 has 20 divisors (see below), whose sum is σ = 341391336. Its totient is φ = 126962640.

The previous prime is 209489239. The next prime is 209489281. The reversal of 209489247 is 742984902.

It is not a de Polignac number, because 209489247 - 2³ = 209489239 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209489237) 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 in 19 ways as a sum of consecutive naturals, for example, 116668 + ... + 118449.

Almost surely, 2^209489247 is an apocalyptic number.

209489247 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

209489247 is a deficient number, since it is larger than the sum of its proper divisors (131902089).

209489247 is a wasteful number, since it uses less digits than its factorization.

209489247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235140 (or 235131 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 209489247 is about 14473.7433651423. The cubic root of 209489247 is about 593.9099189997.

The spelling of 209489247 in words is "two hundred nine million, four hundred eighty-nine thousand, two hundred forty-seven".