812215537817 has 4 divisors (see below), whose sum is σ = 814100029056. Its totient is φ = 810331046580.

The previous prime is 812215537813. The next prime is 812215537907. The reversal of 812215537817 is 718735512218.

812215537817 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.

It is a cyclic number.

It is not a de Polignac number, because 812215537817 - 2² = 812215537813 is a prime.

It is a super-3 number, since 3×812215537817³ (a number of 37 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (812215537813) 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, 942244973 + ... + 942245834.

It is an arithmetic number, because the mean of its divisors is an integer number (203525007264).

Almost surely, 2^812215537817 is an apocalyptic number.

It is an amenable number.

812215537817 is a deficient number, since it is larger than the sum of its proper divisors (1884491239).

812215537817 is a wasteful number, since it uses less digits than its factorization.

812215537817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1884491238.

The product of its digits is 940800, while the sum is 50.

The spelling of 812215537817 in words is "eight hundred twelve billion, two hundred fifteen million, five hundred thirty-seven thousand, eight hundred seventeen".