812121217 has 8 divisors (see below), whose sum is σ = 824886720. Its totient is φ = 799392720.

The previous prime is 812121203. The next prime is 812121223. The reversal of 812121217 is 712121218.

It is a happy number.

812121217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-812121217 is a prime.

It is a super-2 number, since 2×812121217² = 1319081742203122178, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 812121191 and 812121200.

It is not an unprimeable number, because it can be changed into a prime (812121227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36759 + ... + 54547.

It is an arithmetic number, because the mean of its divisors is an integer number (103110840).

Almost surely, 2^812121217 is an apocalyptic number.

It is an amenable number.

812121217 is a deficient number, since it is larger than the sum of its proper divisors (12765503).

812121217 is a wasteful number, since it uses less digits than its factorization.

812121217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18503.

The product of its digits is 448, while the sum is 25.

The square root of 812121217 is about 28497.7405595602. The cubic root of 812121217 is about 932.9827603290.

Subtracting from 812121217 its reverse (712121218), we obtain a palindrome (99999999).

The spelling of 812121217 in words is "eight hundred twelve million, one hundred twenty-one thousand, two hundred seventeen".