211221211021221 has 16 divisors (see below), whose sum is σ = 282074621947904. Its totient is φ = 140591082687984.

The previous prime is 211221211021213. The next prime is 211221211021243. The reversal of 211221211021221 is 122120112122112.

It is not a de Polignac number, because 211221211021221 - 2³ = 211221211021213 is a prime.

It is a super-2 number, since 2×211221211021221² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221211021201) 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, 6511045 + ... + 21560058.

It is an arithmetic number, because the mean of its divisors is an integer number (17629663871744).

Almost surely, 2^{211221211021221} is an apocalyptic number.

It is an amenable number.

211221211021221 is a deficient number, since it is larger than the sum of its proper divisors (70853410926683).

211221211021221 is a wasteful number, since it uses less digits than its factorization.

211221211021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28075080.

The product of its (nonzero) digits is 128, while the sum is 21.

Adding to 211221211021221 its reverse (122120112122112), we get a palindrome (333341323143333).

The spelling of 211221211021221 in words is "two hundred eleven trillion, two hundred twenty-one billion, two hundred eleven million, twenty-one thousand, two hundred twenty-one".