815800217117 has 4 divisors (see below), whose sum is σ = 815951101056. Its totient is φ = 815649333180.

The previous prime is 815800217087. The next prime is 815800217143. The reversal of 815800217117 is 711712008518.

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 815800217117 - 2¹² = 815800213021 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 (815800217017) 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, 75433859 + ... + 75444672.

It is an arithmetic number, because the mean of its divisors is an integer number (203987775264).

Almost surely, 2^815800217117 is an apocalyptic number.

It is an amenable number.

815800217117 is a deficient number, since it is larger than the sum of its proper divisors (150883939).

815800217117 is a wasteful number, since it uses less digits than its factorization.

815800217117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150883938.

The product of its (nonzero) digits is 31360, while the sum is 41.

The spelling of 815800217117 in words is "eight hundred fifteen billion, eight hundred million, two hundred seventeen thousand, one hundred seventeen".