21020021210 has 16 divisors (see below), whose sum is σ = 37945082016. Its totient is φ = 8383776528.

The previous prime is 21020021203. The next prime is 21020021213. The reversal of 21020021210 is 1212002012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21020021191 and 21020021200.

It is not an unprimeable number, because it can be changed into a prime (21020021213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3025352 + ... + 3032291.

It is an arithmetic number, because the mean of its divisors is an integer number (2371567626).

Almost surely, 2^21020021210 is an apocalyptic number.

21020021210 is a deficient number, since it is larger than the sum of its proper divisors (16925060806).

21020021210 is a wasteful number, since it uses less digits than its factorization.

21020021210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6057997.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21020021210 its reverse (1212002012), we get a palindrome (22232023222).

The spelling of 21020021210 in words is "twenty-one billion, twenty million, twenty-one thousand, two hundred ten".