816650209 has 4 divisors (see below), whose sum is σ = 823877316. Its totient is φ = 809423104.

The previous prime is 816650183. The next prime is 816650227. The reversal of 816650209 is 902056618.

816650209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 350737984 + 465912225 = 18728^2 + 21585^2 .

It is a cyclic number.

It is not a de Polignac number, because 816650209 - 2¹⁵ = 816617441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816650269) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3613384 + ... + 3613609.

It is an arithmetic number, because the mean of its divisors is an integer number (205969329).

Almost surely, 2^816650209 is an apocalyptic number.

It is an amenable number.

816650209 is a deficient number, since it is larger than the sum of its proper divisors (7227107).

816650209 is a wasteful number, since it uses less digits than its factorization.

816650209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7227106.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 816650209 is about 28577.0923818362. The cubic root of 816650209 is about 934.7138815887.

The spelling of 816650209 in words is "eight hundred sixteen million, six hundred fifty thousand, two hundred nine".