21221021210212 has 12 divisors (see below), whose sum is σ = 37136854695276. Its totient is φ = 10610491297280.

The previous prime is 21221021210203. The next prime is 21221021210227. The reversal of 21221021210212 is 21201212012212.

It can be written as a sum of positive squares in 2 ways, for example, as 7186227549796 + 14034793660416 = 2680714^2 + 3746304^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21221021210212.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2194489 + ... + 6874432.

It is an arithmetic number, because the mean of its divisors is an integer number (3094737891273).

Almost surely, 2^{21221021210212} is an apocalyptic number.

It is an amenable number.

21221021210212 is a deficient number, since it is larger than the sum of its proper divisors (15915833485064).

21221021210212 is a wasteful number, since it uses less digits than its factorization.

21221021210212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9653918 (or 9653916 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21221021210212 its reverse (21201212012212), we get a palindrome (42422233222424).

The spelling of 21221021210212 in words is "twenty-one trillion, two hundred twenty-one billion, twenty-one million, two hundred ten thousand, two hundred twelve".