211211001221 has 4 divisors (see below), whose sum is σ = 230412001344. Its totient is φ = 192010001100.

The previous prime is 211211001191. The next prime is 211211001227. The reversal of 211211001221 is 122100112112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 211211001221 - 2¹⁰ = 211211000197 is a prime.

It is a super-2 number, since 2×211211001221² (a number of 23 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 = 211211001196 and 211211001205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211211001227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9600500045 + ... + 9600500066.

It is an arithmetic number, because the mean of its divisors is an integer number (57603000336).

Almost surely, 2^211211001221 is an apocalyptic number.

It is an amenable number.

211211001221 is a deficient number, since it is larger than the sum of its proper divisors (19201000123).

211211001221 is a wasteful number, since it uses less digits than its factorization.

211211001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19201000122.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 211211001221 its reverse (122100112112), we get a palindrome (333311113333).

The spelling of 211211001221 in words is "two hundred eleven billion, two hundred eleven million, one thousand, two hundred twenty-one".