209642949 has 12 divisors (see below), whose sum is σ = 304633056. Its totient is φ = 138924072.

The previous prime is 209642921. The next prime is 209643013. The reversal of 209642949 is 949246902.

It is a happy number.

It is not a de Polignac number, because 209642949 - 2⁷ = 209642821 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209642749) 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 11 ways as a sum of consecutive naturals, for example, 68239 + ... + 71244.

It is an arithmetic number, because the mean of its divisors is an integer number (25386088).

Almost surely, 2^209642949 is an apocalyptic number.

It is an amenable number.

209642949 is a deficient number, since it is larger than the sum of its proper divisors (94990107).

209642949 is a wasteful number, since it uses less digits than its factorization.

209642949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139656 (or 139653 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 209642949 is about 14479.0520753259. The cubic root of 209642949 is about 594.0551338138.

The spelling of 209642949 in words is "two hundred nine million, six hundred forty-two thousand, nine hundred forty-nine".