209409994 has 4 divisors (see below), whose sum is σ = 314114994. Its totient is φ = 104704996.

The previous prime is 209409983. The next prime is 209410013. The reversal of 209409994 is 499904902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 140304025 + 69105969 = 11845^2 + 8313^2 .

It is an unprimeable number.

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, 52352497 + ... + 52352500.

Almost surely, 2^209409994 is an apocalyptic number.

209409994 is a deficient number, since it is larger than the sum of its proper divisors (104705000).

209409994 is a wasteful number, since it uses less digits than its factorization.

209409994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104704999.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 209409994 is about 14471.0052864340. The cubic root of 209409994 is about 593.8350144714.

The spelling of 209409994 in words is "two hundred nine million, four hundred nine thousand, nine hundred ninety-four".