21221211111613 has 2 divisors, whose sum is σ = 21221211111614. Its totient is φ = 21221211111612.

The previous prime is 21221211111599. The next prime is 21221211111641. The reversal of 21221211111613 is 31611111212212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15964036232004 + 5257174879609 = 3995502^2 + 2292853^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221211111613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221211111713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610605555806 + 10610605555807.

It is an arithmetic number, because the mean of its divisors is an integer number (10610605555807).

Almost surely, 2^{21221211111613} is an apocalyptic number.

It is an amenable number.

21221211111613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221211111613 is an equidigital number, since it uses as much as digits as its factorization.

21221211111613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 25.

Adding to 21221211111613 its reverse (31611111212212), we get a palindrome (52832322323825).

The spelling of 21221211111613 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred eleven million, one hundred eleven thousand, six hundred thirteen".