816566869 has 2 divisors, whose sum is σ = 816566870. Its totient is φ = 816566868.

The previous prime is 816566867. The next prime is 816566909. The reversal of 816566869 is 968665618.

It is a happy number.

816566869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 523814769 + 292752100 = 22887^2 + 17110^2 .

It is a cyclic number.

It is not a de Polignac number, because 816566869 - 2¹ = 816566867 is a prime.

It is a super-2 number, since 2×816566869² = 1333562903096926322, which contains 22 as substring.

Together with 816566867, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (816566867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408283434 + 408283435.

It is an arithmetic number, because the mean of its divisors is an integer number (408283435).

Almost surely, 2^816566869 is an apocalyptic number.

It is an amenable number.

816566869 is a deficient number, since it is larger than the sum of its proper divisors (1).

816566869 is an equidigital number, since it uses as much as digits as its factorization.

816566869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3732480, while the sum is 55.

The square root of 816566869 is about 28575.6341836887. The cubic root of 816566869 is about 934.6820843336.

The spelling of 816566869 in words is "eight hundred sixteen million, five hundred sixty-six thousand, eight hundred sixty-nine".