817253865 has 12 divisors (see below), whose sum is σ = 1416573444. Its totient is φ = 435868704.

The previous prime is 817253839. The next prime is 817253867. The reversal of 817253865 is 568352718.

It can be written as a sum of positive squares in 2 ways, for example, as 369677529 + 447576336 = 19227^2 + 21156^2 .

It is not a de Polignac number, because 817253865 - 2¹⁰ = 817252841 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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: 18161197 = 817253865 / (8 + 1 + 7 + 2 + 5 + 3 + 8 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 817253865.

It is not an unprimeable number, because it can be changed into a prime (817253867) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9080554 + ... + 9080643.

It is an arithmetic number, because the mean of its divisors is an integer number (118047787).

Almost surely, 2^817253865 is an apocalyptic number.

It is an amenable number.

817253865 is a deficient number, since it is larger than the sum of its proper divisors (599319579).

817253865 is a wasteful number, since it uses less digits than its factorization.

817253865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18161208 (or 18161205 counting only the distinct ones).

The product of its digits is 403200, while the sum is 45.

The square root of 817253865 is about 28587.6523170407. The cubic root of 817253865 is about 934.9441338502.

The spelling of 817253865 in words is "eight hundred seventeen million, two hundred fifty-three thousand, eight hundred sixty-five".