209722849 has 4 divisors (see below), whose sum is σ = 239683264. Its totient is φ = 179762436.

The previous prime is 209722837. The next prime is 209722859. The reversal of 209722849 is 948227902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 948227902 = 2 ⋅474113951.

It is not a de Polignac number, because 209722849 - 2¹¹ = 209720801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209722859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14980197 + ... + 14980210.

It is an arithmetic number, because the mean of its divisors is an integer number (59920816).

Almost surely, 2^209722849 is an apocalyptic number.

It is an amenable number.

209722849 is a deficient number, since it is larger than the sum of its proper divisors (29960415).

209722849 is an equidigital number, since it uses as much as digits as its factorization.

209722849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29960414.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 209722849 is about 14481.8109710077. The cubic root of 209722849 is about 594.1305938228.

The spelling of 209722849 in words is "two hundred nine million, seven hundred twenty-two thousand, eight hundred forty-nine".