211221000121 has 4 divisors (see below), whose sum is σ = 223645764852. Its totient is φ = 198796235392.

The previous prime is 211221000103. The next prime is 211221000161. The reversal of 211221000121 is 121000122112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 152596484496 + 58624515625 = 390636^2 + 242125^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211221000121 is a prime.

It is a super-2 number, since 2×211221000121² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211221000101) 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, 6212382340 + ... + 6212382373.

It is an arithmetic number, because the mean of its divisors is an integer number (55911441213).

Almost surely, 2^211221000121 is an apocalyptic number.

It is an amenable number.

211221000121 is a deficient number, since it is larger than the sum of its proper divisors (12424764731).

211221000121 is a wasteful number, since it uses less digits than its factorization.

211221000121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12424764730.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 211221000121 its reverse (121000122112), we get a palindrome (332221122233).

The spelling of 211221000121 in words is "two hundred eleven billion, two hundred twenty-one million, one hundred twenty-one", and thus it is an aban number.