813864109 has 4 divisors (see below), whose sum is σ = 813924540. Its totient is φ = 813803680.

The previous prime is 813864067. The next prime is 813864119. The reversal of 813864109 is 901468318.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 901468318 = 2 ⋅450734159.

It can be written as a sum of positive squares in 2 ways, for example, as 398601225 + 415262884 = 19965^2 + 20378^2 .

It is a cyclic number.

It is not a de Polignac number, because 813864109 - 2²³ = 805475501 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 (813864119) 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, 177 + ... + 40345.

It is an arithmetic number, because the mean of its divisors is an integer number (203481135).

Almost surely, 2^813864109 is an apocalyptic number.

It is an amenable number.

813864109 is a deficient number, since it is larger than the sum of its proper divisors (60431).

813864109 is a wasteful number, since it uses less digits than its factorization.

813864109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60430.

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 813864109 is about 28528.3036474306. The cubic root of 813864109 is about 933.6497076975.

The spelling of 813864109 in words is "eight hundred thirteen million, eight hundred sixty-four thousand, one hundred nine".