209564242 has 16 divisors (see below), whose sum is σ = 318543192. Its totient is φ = 103392640.

The previous prime is 209564231. The next prime is 209564261. The reversal of 209564242 is 242465902.

It can be written as a sum of positive squares in 4 ways, for example, as 208484721 + 1079521 = 14439^2 + 1039^2 .

It is a junction number, because it is equal to n+sod(n) for n = 209564198 and 209564207.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45192 + ... + 49612.

Almost surely, 2^209564242 is an apocalyptic number.

209564242 is a deficient number, since it is larger than the sum of its proper divisors (108978950).

209564242 is a wasteful number, since it uses less digits than its factorization.

209564242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4733.

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 209564242 is about 14476.3338590957. Note that the first 3 decimals coincide. The cubic root of 209564242 is about 593.9807817625.

The spelling of 209564242 in words is "two hundred nine million, five hundred sixty-four thousand, two hundred forty-two".