216766813 has 4 divisors (see below), whose sum is σ = 229517820. Its totient is φ = 204015808.

The previous prime is 216766811. The next prime is 216766817. The reversal of 216766813 is 318667612.

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 2 ways, for example, as 85045284 + 131721529 = 9222^2 + 11477^2 .

It is a cyclic number.

It is not a de Polignac number, because 216766813 - 2¹ = 216766811 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216766811) 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 3 ways as a sum of consecutive naturals, for example, 6375478 + ... + 6375511.

It is an arithmetic number, because the mean of its divisors is an integer number (57379455).

Almost surely, 2^216766813 is an apocalyptic number.

It is an amenable number.

216766813 is a deficient number, since it is larger than the sum of its proper divisors (12751007).

216766813 is a wasteful number, since it uses less digits than its factorization.

216766813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12751006.

The product of its digits is 72576, while the sum is 40.

The square root of 216766813 is about 14723.0028526792. The cubic root of 216766813 is about 600.7091734951.

The spelling of 216766813 in words is "two hundred sixteen million, seven hundred sixty-six thousand, eight hundred thirteen".