816786405 has 12 divisors (see below), whose sum is σ = 1415763180. Its totient is φ = 435619392.

The previous prime is 816786367. The next prime is 816786407. The reversal of 816786405 is 504687618.

It is a happy number.

816786405 is a `hidden beast` number, since 8 + 167 + 86 + 405 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 201696804 + 615089601 = 14202^2 + 24801^2 .

It is not a de Polignac number, because 816786405 - 2¹⁴ = 816770021 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 18150809 = 816786405 / (8 + 1 + 6 + 7 + 8 + 6 + 4 + 0 + 5).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816786407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9075360 + ... + 9075449.

It is an arithmetic number, because the mean of its divisors is an integer number (117980265).

Almost surely, 2^816786405 is an apocalyptic number.

It is an amenable number.

816786405 is a deficient number, since it is larger than the sum of its proper divisors (598976775).

816786405 is a wasteful number, since it uses less digits than its factorization.

816786405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18150820 (or 18150817 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The square root of 816786405 is about 28579.4752401089. The cubic root of 816786405 is about 934.7658406829.

Subtracting from 816786405 its product of nonzero digits (322560), we obtain a triangular number (816463845 = T₄₀₄₀₉).

The spelling of 816786405 in words is "eight hundred sixteen million, seven hundred eighty-six thousand, four hundred five".