21221201212361 has 2 divisors, whose sum is σ = 21221201212362. Its totient is φ = 21221201212360.

The previous prime is 21221201212349. The next prime is 21221201212399. The reversal of 21221201212361 is 16321210212212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21220358181136 + 843031225 = 4606556^2 + 29035^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221201212361 - 2¹⁰ = 21221201211337 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21221201212361.

It is not a weakly prime, because it can be changed into another prime (21221201212061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610600606180 + 10610600606181.

It is an arithmetic number, because the mean of its divisors is an integer number (10610600606181).

Almost surely, 2^{21221201212361} is an apocalyptic number.

It is an amenable number.

21221201212361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221201212361 is an equidigital number, since it uses as much as digits as its factorization.

21221201212361 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

Adding to 21221201212361 its reverse (16321210212212), we get a palindrome (37542411424573).

The spelling of 21221201212361 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twelve thousand, three hundred sixty-one".