816397693 has 4 divisors (see below), whose sum is σ = 816633340. Its totient is φ = 816162048.

The previous prime is 816397667. The next prime is 816397721. The reversal of 816397693 is 396793618.

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 417916249 + 398481444 = 20443^2 + 19962^2 .

It is a cyclic number.

It is not a de Polignac number, because 816397693 - 2⁹ = 816397181 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 816397693.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816394693) 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, 112548 + ... + 119581.

It is an arithmetic number, because the mean of its divisors is an integer number (204158335).

Almost surely, 2^816397693 is an apocalyptic number.

It is an amenable number.

816397693 is a deficient number, since it is larger than the sum of its proper divisors (235647).

816397693 is a wasteful number, since it uses less digits than its factorization.

816397693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235646.

The product of its digits is 1469664, while the sum is 52.

The square root of 816397693 is about 28572.6738860751. The cubic root of 816397693 is about 934.6175308542.

The spelling of 816397693 in words is "eight hundred sixteen million, three hundred ninety-seven thousand, six hundred ninety-three".