21100001213 has 2 divisors, whose sum is σ = 21100001214. Its totient is φ = 21100001212.

The previous prime is 21100001207. The next prime is 21100001227. The reversal of 21100001213 is 31210000112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11121389764 + 9978611449 = 105458^2 + 99893^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21100001213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21100001194 and 21100001203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100001513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550000606 + 10550000607.

It is an arithmetic number, because the mean of its divisors is an integer number (10550000607).

Almost surely, 2^21100001213 is an apocalyptic number.

It is an amenable number.

21100001213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100001213 is an equidigital number, since it uses as much as digits as its factorization.

21100001213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 21100001213 its reverse (31210000112), we get a palindrome (52310001325).

The spelling of 21100001213 in words is "twenty-one billion, one hundred million, one thousand, two hundred thirteen".