810831078509 has 4 divisors (see below), whose sum is σ = 810832950816. Its totient is φ = 810829206204.

The previous prime is 810831078503. The next prime is 810831078511. The reversal of 810831078509 is 905870138018.

810831078509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 905870138018 = 2 ⋅452935069009.

It is a cyclic number.

It is not a de Polignac number, because 810831078509 - 2¹⁶ = 810831012973 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810831078503) 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, 84032 + ... + 1276214.

It is an arithmetic number, because the mean of its divisors is an integer number (202708237704).

Almost surely, 2^810831078509 is an apocalyptic number.

It is an amenable number.

810831078509 is a deficient number, since it is larger than the sum of its proper divisors (1872307).

810831078509 is a wasteful number, since it uses less digits than its factorization.

810831078509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1872306.

The product of its (nonzero) digits is 483840, while the sum is 50.

The spelling of 810831078509 in words is "eight hundred ten billion, eight hundred thirty-one million, seventy-eight thousand, five hundred nine".