12105321217 has 16 divisors (see below), whose sum is σ = 13639760064. Its totient is φ = 10736378400.

The previous prime is 12105321197. The next prime is 12105321251. The reversal of 12105321217 is 71212350121.

It is not a de Polignac number, because 12105321217 - 2²³ = 12096932609 is a prime.

It is a super-2 number, since 2×12105321217² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12105321191 and 12105321200.

It is not an unprimeable number, because it can be changed into a prime (12105321617) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56343 + ... + 165484.

It is an arithmetic number, because the mean of its divisors is an integer number (852485004).

Almost surely, 2^12105321217 is an apocalyptic number.

It is an amenable number.

12105321217 is a deficient number, since it is larger than the sum of its proper divisors (1534438847).

12105321217 is an equidigital number, since it uses as much as digits as its factorization.

12105321217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221901 (or 221879 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 25.

Adding to 12105321217 its reverse (71212350121), we get a palindrome (83317671338).

The spelling of 12105321217 in words is "twelve billion, one hundred five million, three hundred twenty-one thousand, two hundred seventeen".