21120020001221 has 2 divisors, whose sum is σ = 21120020001222. Its totient is φ = 21120020001220.

The previous prime is 21120020001131. The next prime is 21120020001229. The reversal of 21120020001221 is 12210002002112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20300296192225 + 819723808996 = 4505585^2 + 905386^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120020001221 - 2²² = 21120015806917 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120020001196 and 21120020001205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120020001229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560010000610 + 10560010000611.

It is an arithmetic number, because the mean of its divisors is an integer number (10560010000611).

Almost surely, 2^{21120020001221} is an apocalyptic number.

It is an amenable number.

21120020001221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120020001221 is an equidigital number, since it uses as much as digits as its factorization.

21120020001221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21120020001221 its reverse (12210002002112), we get a palindrome (33330022003333).

The spelling of 21120020001221 in words is "twenty-one trillion, one hundred twenty billion, twenty million, one thousand, two hundred twenty-one".