816005778 has 32 divisors (see below), whose sum is σ = 1868075136. Its totient is φ = 232779648.

The previous prime is 816005767. The next prime is 816005819. The reversal of 816005778 is 877500618.

It is a Harshad number since it is a multiple of its sum of digits (42).

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 15 ways as a sum of consecutive naturals, for example, 12550 + ... + 42302.

It is an arithmetic number, because the mean of its divisors is an integer number (58377348).

Almost surely, 2^816005778 is an apocalyptic number.

816005778 is an abundant number, since it is smaller than the sum of its proper divisors (1052069358).

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

816005778 is a wasteful number, since it uses less digits than its factorization.

816005778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30418.

The product of its (nonzero) digits is 94080, while the sum is 42.

The square root of 816005778 is about 28565.8148492214. The cubic root of 816005778 is about 934.4679512798.

It can be divided in two parts, 81600 and 5778, that added together give a palindrome (87378).

The spelling of 816005778 in words is "eight hundred sixteen million, five thousand, seven hundred seventy-eight".