21113423421221 has 2 divisors, whose sum is σ = 21113423421222. Its totient is φ = 21113423421220.

The previous prime is 21113423421161. The next prime is 21113423421283. The reversal of 21113423421221 is 12212432431112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20860786504321 + 252636916900 = 4567361^2 + 502630^2 .

It is a cyclic number.

It is not a de Polignac number, because 21113423421221 - 2³⁰ = 21112349679397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21113423421121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556711710610 + 10556711710611.

It is an arithmetic number, because the mean of its divisors is an integer number (10556711710611).

Almost surely, 2^{21113423421221} is an apocalyptic number.

It is an amenable number.

21113423421221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113423421221 is an equidigital number, since it uses as much as digits as its factorization.

21113423421221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 29.

Adding to 21113423421221 its reverse (12212432431112), we get a palindrome (33325855852333).

The spelling of 21113423421221 in words is "twenty-one trillion, one hundred thirteen billion, four hundred twenty-three million, four hundred twenty-one thousand, two hundred twenty-one".