21110202021 has 4 divisors (see below), whose sum is σ = 28146936032. Its totient is φ = 14073468012.

The previous prime is 21110201953. The next prime is 21110202049. The reversal of 21110202021 is 12020201112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21110202021 - 2³¹ = 18962718373 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21110201988 and 21110202006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110202121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3518367001 + ... + 3518367006.

It is an arithmetic number, because the mean of its divisors is an integer number (7036734008).

Almost surely, 2^21110202021 is an apocalyptic number.

It is an amenable number.

21110202021 is a deficient number, since it is larger than the sum of its proper divisors (7036734011).

21110202021 is an equidigital number, since it uses as much as digits as its factorization.

21110202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7036734010.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21110202021 its reverse (12020201112), we get a palindrome (33130403133).

Subtracting from 21110202021 its reverse (12020201112), we obtain a palindrome (9090000909).

The spelling of 21110202021 in words is "twenty-one billion, one hundred ten million, two hundred two thousand, twenty-one".