21021011210 has 16 divisors (see below), whose sum is σ = 37925213256. Its totient is φ = 8388983808.

The previous prime is 21021011191. The next prime is 21021011213. The reversal of 21021011210 is 1211012012.

It can be written as a sum of positive squares in 4 ways, for example, as 13770318409 + 7250692801 = 117347^2 + 85151^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21021011191 and 21021011200.

It is not an unprimeable number, because it can be changed into a prime (21021011213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2423039 + ... + 2431698.

Almost surely, 2^21021011210 is an apocalyptic number.

21021011210 is a deficient number, since it is larger than the sum of its proper divisors (16904202046).

21021011210 is a wasteful number, since it uses less digits than its factorization.

21021011210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4855177.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21021011210 its reverse (1211012012), we get a palindrome (22232023222).

The spelling of 21021011210 in words is "twenty-one billion, twenty-one million, eleven thousand, two hundred ten".