211221225421 has 2 divisors, whose sum is σ = 211221225422. Its totient is φ = 211221225420.

The previous prime is 211221225377. The next prime is 211221225431. The reversal of 211221225421 is 124522122112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 131366378025 + 79854847396 = 362445^2 + 282586^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221225421 - 2²¹ = 211219128269 is a prime.

It is a super-3 number, since 3×211221225421³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211221225431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610612710 + 105610612711.

It is an arithmetic number, because the mean of its divisors is an integer number (105610612711).

Almost surely, 2^211221225421 is an apocalyptic number.

It is an amenable number.

211221225421 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221225421 is an equidigital number, since it uses as much as digits as its factorization.

211221225421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1280, while the sum is 25.

Adding to 211221225421 its reverse (124522122112), we get a palindrome (335743347533).

The spelling of 211221225421 in words is "two hundred eleven billion, two hundred twenty-one million, two hundred twenty-five thousand, four hundred twenty-one".