21101243213 has 2 divisors, whose sum is σ = 21101243214. Its totient is φ = 21101243212.

The previous prime is 21101243203. The next prime is 21101243263. The reversal of 21101243213 is 31234210112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20295421444 + 805821769 = 142462^2 + 28387^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101243213 - 2⁴ = 21101243197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101243203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550621606 + 10550621607.

It is an arithmetic number, because the mean of its divisors is an integer number (10550621607).

Almost surely, 2^21101243213 is an apocalyptic number.

It is an amenable number.

21101243213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101243213 is an equidigital number, since it uses as much as digits as its factorization.

21101243213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21101243213 its reverse (31234210112), we get a palindrome (52335453325).

The spelling of 21101243213 in words is "twenty-one billion, one hundred one million, two hundred forty-three thousand, two hundred thirteen".