816390820 has 24 divisors (see below), whose sum is σ = 1959338304. Its totient is φ = 279905376.

The previous prime is 816390787. The next prime is 816390833. The reversal of 816390820 is 28093618.

It is a self number, because there is not a number n which added to its sum of digits gives 816390820.

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 in 7 ways as a sum of consecutive naturals, for example, 2915542 + ... + 2915821.

It is an arithmetic number, because the mean of its divisors is an integer number (81639096).

Almost surely, 2^816390820 is an apocalyptic number.

It is an amenable number.

816390820 is an abundant number, since it is smaller than the sum of its proper divisors (1142947484).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

816390820 is a wasteful number, since it uses less digits than its factorization.

816390820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5831379 (or 5831377 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 816390820 is about 28572.5536135642. The cubic root of 816390820 is about 934.6149080948.

The spelling of 816390820 in words is "eight hundred sixteen million, three hundred ninety thousand, eight hundred twenty".