853661817893 has 4 divisors (see below), whose sum is σ = 853663727148. Its totient is φ = 853659908640.

The previous prime is 853661817857. The next prime is 853661817947. The reversal of 853661817893 is 398718166358.

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 564268387684 + 289393430209 = 751178^2 + 537953^2 .

It is a cyclic number.

It is not a de Polignac number, because 853661817893 - 2¹⁰ = 853661816869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (853661816893) 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, 117155 + ... + 1311887.

It is an arithmetic number, because the mean of its divisors is an integer number (213415931787).

Almost surely, 2^853661817893 is an apocalyptic number.

It is an amenable number.

853661817893 is a deficient number, since it is larger than the sum of its proper divisors (1909255).

853661817893 is a wasteful number, since it uses less digits than its factorization.

853661817893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909254.

The product of its digits is 52254720, while the sum is 65.

The spelling of 853661817893 in words is "eight hundred fifty-three billion, six hundred sixty-one million, eight hundred seventeen thousand, eight hundred ninety-three".