816616709 has 4 divisors (see below), whose sum is σ = 864653004. Its totient is φ = 768580416.

The previous prime is 816616667. The next prime is 816616711. The reversal of 816616709 is 907616618.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 907616618 = 2 ⋅453808309.

It can be written as a sum of positive squares in 2 ways, for example, as 691847809 + 124768900 = 26303^2 + 11170^2 .

It is a cyclic number.

It is not a de Polignac number, because 816616709 - 2⁸ = 816616453 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 816616709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816616609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24018122 + ... + 24018155.

It is an arithmetic number, because the mean of its divisors is an integer number (216163251).

Almost surely, 2^816616709 is an apocalyptic number.

It is an amenable number.

816616709 is a deficient number, since it is larger than the sum of its proper divisors (48036295).

816616709 is a wasteful number, since it uses less digits than its factorization.

816616709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48036294.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 816616709 is about 28576.5062420164. The cubic root of 816616709 is about 934.7011003747.

Subtracting 816616709 from its reverse (907616618), we obtain a palindrome (90999909).

The spelling of 816616709 in words is "eight hundred sixteen million, six hundred sixteen thousand, seven hundred nine".