21002110013813 has 2 divisors, whose sum is σ = 21002110013814. Its totient is φ = 21002110013812.

The previous prime is 21002110013809. The next prime is 21002110013849. The reversal of 21002110013813 is 31831001120012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12382354586449 + 8619755427364 = 3518857^2 + 2935942^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002110013813 - 2² = 21002110013809 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002110013873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501055006906 + 10501055006907.

It is an arithmetic number, because the mean of its divisors is an integer number (10501055006907).

Almost surely, 2^{21002110013813} is an apocalyptic number.

It is an amenable number.

21002110013813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002110013813 is an equidigital number, since it uses as much as digits as its factorization.

21002110013813 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 23.

Adding to 21002110013813 its reverse (31831001120012), we get a palindrome (52833111133825).

The spelling of 21002110013813 in words is "twenty-one trillion, two billion, one hundred ten million, thirteen thousand, eight hundred thirteen".