1212122100221 has 8 divisors (see below), whose sum is σ = 1283550140664. Its totient is φ = 1140708142080.

The previous prime is 1212122100197. The next prime is 1212122100251. The reversal of 1212122100221 is 1220012212121.

It can be written as a sum of positive squares in 4 ways, for example, as 416483076025 + 795639024196 = 645355^2 + 891986^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1212122100221 - 2¹⁰ = 1212122099197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1212122100221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212122100251) 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, 3343100 + ... + 3687893.

It is an arithmetic number, because the mean of its divisors is an integer number (160443767583).

Almost surely, 2^{1212122100221} is an apocalyptic number.

It is an amenable number.

1212122100221 is a deficient number, since it is larger than the sum of its proper divisors (71428040443).

1212122100221 is a wasteful number, since it uses less digits than its factorization.

1212122100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7041151.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1212122100221 its reverse (1220012212121), we get a palindrome (2432134312342).

The spelling of 1212122100221 in words is "one trillion, two hundred twelve billion, one hundred twenty-two million, one hundred thousand, two hundred twenty-one".