211221021221 has 8 divisors (see below), whose sum is σ = 241558459584. Its totient is φ = 180924334560.

The previous prime is 211221021173. The next prime is 211221021229. The reversal of 211221021221 is 122120122112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211221021221 is a prime.

It is a super-2 number, since 2×211221021221² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 211221021221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221021229) 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, 10176815 + ... + 10197548.

It is an arithmetic number, because the mean of its divisors is an integer number (30194807448).

Almost surely, 2^211221021221 is an apocalyptic number.

It is an amenable number.

211221021221 is a deficient number, since it is larger than the sum of its proper divisors (30337438363).

211221021221 is a wasteful number, since it uses less digits than its factorization.

211221021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20375851.

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

Adding to 211221021221 its reverse (122120122112), we get a palindrome (333341143333).

The spelling of 211221021221 in words is "two hundred eleven billion, two hundred twenty-one million, twenty-one thousand, two hundred twenty-one".