8121217 has 4 divisors (see below), whose sum is σ = 8745940. Its totient is φ = 7496496.

The previous prime is 8121209. The next prime is 8121283. The reversal of 8121217 is 7121218.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2509056 + 5612161 = 1584^2 + 2369^2 .

It is a cyclic number.

It is not a de Polignac number, because 8121217 - 2³ = 8121209 is a prime.

It is a super-2 number, since 2×8121217² = 131908331122178, which contains 22 as substring.

It is a Duffinian number.

8121217 is a lucky number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (8124217) 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, 312342 + ... + 312367.

It is an arithmetic number, because the mean of its divisors is an integer number (2186485).

Almost surely, 2^8121217 is an apocalyptic number.

It is an amenable number.

8121217 is a deficient number, since it is larger than the sum of its proper divisors (624723).

8121217 is a wasteful number, since it uses less digits than its factorization.

8121217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 624722.

The product of its digits is 224, while the sum is 22.

The square root of 8121217 is about 2849.7749033915. The cubic root of 8121217 is about 201.0050822539.

Subtracting from 8121217 its reverse (7121218), we obtain a palindrome (999999).

It can be divided in two parts, 8121 and 217, that added together give a palindrome (8338).

The spelling of 8121217 in words is "eight million, one hundred twenty-one thousand, two hundred seventeen".