1211212110221 has 8 divisors (see below), whose sum is σ = 1216471047480. Its totient is φ = 1205953691392.

The previous prime is 1211212110187. The next prime is 1211212110259. The reversal of 1211212110221 is 1220112121121.

It can be written as a sum of positive squares in 4 ways, for example, as 339089594596 + 872122515625 = 582314^2 + 933875^2 .

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 1211212110221 - 2¹⁰ = 1211212109197 is a prime.

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 1211212110221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211212110421) 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, 4990931 + ... + 5227983.

It is an arithmetic number, because the mean of its divisors is an integer number (152058880935).

Almost surely, 2^{1211212110221} is an apocalyptic number.

It is an amenable number.

1211212110221 is a deficient number, since it is larger than the sum of its proper divisors (5258937259).

1211212110221 is a wasteful number, since it uses less digits than its factorization.

1211212110221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259215.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1211212110221 its reverse (1220112121121), we get a palindrome (2431324231342).

The spelling of 1211212110221 in words is "one trillion, two hundred eleven billion, two hundred twelve million, one hundred ten thousand, two hundred twenty-one".