21203211021 has 12 divisors (see below), whose sum is σ = 28418338368. Its totient is φ = 14062159104.

The previous prime is 21203211013. The next prime is 21203211031. The reversal of 21203211021 is 12011230212.

It is not a de Polignac number, because 21203211021 - 2³ = 21203211013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203211031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16876 + ... + 206618.

It is an arithmetic number, because the mean of its divisors is an integer number (2368194864).

Almost surely, 2^21203211021 is an apocalyptic number.

It is an amenable number.

21203211021 is a deficient number, since it is larger than the sum of its proper divisors (7215127347).

21203211021 is an equidigital number, since it uses as much as digits as its factorization.

21203211021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190132 (or 189939 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21203211021 its reverse (12011230212), we get a palindrome (33214441233).

The spelling of 21203211021 in words is "twenty-one billion, two hundred three million, two hundred eleven thousand, twenty-one".