816390818 has 4 divisors (see below), whose sum is σ = 1224586230. Its totient is φ = 408195408.

The previous prime is 816390787. The next prime is 816390833. The reversal of 816390818 is 818093618.

It is a happy number.

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., 657050689 + 159340129 = 25633^2 + 12623^2 .

It is a Curzon number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 204097703 + ... + 204097706.

Almost surely, 2^816390818 is an apocalyptic number.

816390818 is a deficient number, since it is larger than the sum of its proper divisors (408195412).

816390818 is a wasteful number, since it uses less digits than its factorization.

816390818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408195411.

The product of its (nonzero) digits is 82944, while the sum is 44.

The square root of 816390818 is about 28572.5535785656. The cubic root of 816390818 is about 934.6149073316.

The spelling of 816390818 in words is "eight hundred sixteen million, three hundred ninety thousand, eight hundred eighteen".