816855939 has 12 divisors (see below), whose sum is σ = 1186497000. Its totient is φ = 541527264.

The previous prime is 816855937. The next prime is 816855947. The reversal of 816855939 is 939558618.

It is a happy number.

816855939 is a `hidden beast` number, since 81 + 6 + 8 + 559 + 3 + 9 = 666.

It is not a de Polignac number, because 816855939 - 2¹ = 816855937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (816855931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 251914 + ... + 255135.

It is an arithmetic number, because the mean of its divisors is an integer number (98874750).

Almost surely, 2^816855939 is an apocalyptic number.

816855939 is a deficient number, since it is larger than the sum of its proper divisors (369641061).

816855939 is a wasteful number, since it uses less digits than its factorization.

816855939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507234 (or 507231 counting only the distinct ones).

The product of its digits is 2332800, while the sum is 54.

The square root of 816855939 is about 28580.6917166118. The cubic root of 816855939 is about 934.7923658402.

The spelling of 816855939 in words is "eight hundred sixteen million, eight hundred fifty-five thousand, nine hundred thirty-nine".