211221211222121 has 8 divisors (see below), whose sum is σ = 223855198838280. Its totient is φ = 198610469215488.

The previous prime is 211221211222117. The next prime is 211221211222141. The reversal of 211221211222121 is 121222112122112.

It can be written as a sum of positive squares in 4 ways, for example, as 121990611244096 + 89230599978025 = 11044936^2 + 9446195^2 .

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 211221211222121 - 2² = 211221211222117 is a prime.

It is a super-2 number, since 2×211221211222121² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (211221211222141) 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, 5811383666 + ... + 5811420011.

It is an arithmetic number, because the mean of its divisors is an integer number (27981899854785).

Almost surely, 2^{211221211222121} is an apocalyptic number.

It is an amenable number.

211221211222121 is a deficient number, since it is larger than the sum of its proper divisors (12633987616159).

211221211222121 is a wasteful number, since it uses less digits than its factorization.

211221211222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11622804763.

The product of its digits is 256, while the sum is 23.

Adding to 211221211222121 its reverse (121222112122112), we get a palindrome (332443323344233).

The spelling of 211221211222121 in words is "two hundred eleven trillion, two hundred twenty-one billion, two hundred eleven million, two hundred twenty-two thousand, one hundred twenty-one".