853840665 has 12 divisors (see below), whose sum is σ = 1479990564. Its totient is φ = 455381664.

The previous prime is 853840651. The next prime is 853840727. The reversal of 853840665 is 566048358.

It can be written as a sum of positive squares in 2 ways, for example, as 137100681 + 716739984 = 11709^2 + 26772^2 .

It is not a de Polignac number, because 853840665 - 2¹⁰ = 853839641 is a prime.

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: 18974237 = 853840665 / (8 + 5 + 3 + 8 + 4 + 0 + 6 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 853840665.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9487074 + ... + 9487163.

It is an arithmetic number, because the mean of its divisors is an integer number (123332547).

Almost surely, 2^853840665 is an apocalyptic number.

It is an amenable number.

853840665 is a deficient number, since it is larger than the sum of its proper divisors (626149899).

853840665 is a wasteful number, since it uses less digits than its factorization.

853840665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18974248 (or 18974245 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 45.

The square root of 853840665 is about 29220.5520995069. The cubic root of 853840665 is about 948.6928152715.

The spelling of 853840665 in words is "eight hundred fifty-three million, eight hundred forty thousand, six hundred sixty-five".