21102114821 has 2 divisors, whose sum is σ = 21102114822. Its totient is φ = 21102114820.

The previous prime is 21102114809. The next prime is 21102114829. The reversal of 21102114821 is 12841120112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15920130625 + 5181984196 = 126175^2 + 71986^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102114821 - 2¹⁰ = 21102113797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102114829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551057410 + 10551057411.

It is an arithmetic number, because the mean of its divisors is an integer number (10551057411).

Almost surely, 2^21102114821 is an apocalyptic number.

It is an amenable number.

21102114821 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102114821 is an equidigital number, since it uses as much as digits as its factorization.

21102114821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 23.

Adding to 21102114821 its reverse (12841120112), we get a palindrome (33943234933).

The spelling of 21102114821 in words is "twenty-one billion, one hundred two million, one hundred fourteen thousand, eight hundred twenty-one".