21020211221210 has 16 divisors (see below), whose sum is σ = 37943565417576. Its totient is φ = 8384265550848.

The previous prime is 21020211221167. The next prime is 21020211221231. The reversal of 21020211221210 is 1212211202012.

It can be written as a sum of positive squares in 4 ways, for example, as 14140014023041 + 6880197198169 = 3760321^2 + 2623013^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2977363499 + ... + 2977370558.

Almost surely, 2^{21020211221210} is an apocalyptic number.

21020211221210 is a deficient number, since it is larger than the sum of its proper divisors (16923354196366).

21020211221210 is a wasteful number, since it uses less digits than its factorization.

21020211221210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5954734417.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21020211221210 its reverse (1212211202012), we get a palindrome (22232422423222).

The spelling of 21020211221210 in words is "twenty-one trillion, twenty billion, two hundred eleven million, two hundred twenty-one thousand, two hundred ten".