21001221122222 has 48 divisors (see below), whose sum is σ = 36558893116800. Its totient is φ = 8971475606400.

The previous prime is 21001221122207. The next prime is 21001221122257. The reversal of 21001221122222 is 22222112210012.

It is a junction number, because it is equal to n+sod(n) for n = 21001221122194 and 21001221122203.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2003279 + ... + 6783477.

It is an arithmetic number, because the mean of its divisors is an integer number (761643606600).

Almost surely, 2^{21001221122222} is an apocalyptic number.

21001221122222 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21001221122222 is a deficient number, since it is larger than the sum of its proper divisors (15557671994578).

21001221122222 is a wasteful number, since it uses less digits than its factorization.

21001221122222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4780937 (or 4780920 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21001221122222 its reverse (22222112210012), we get a palindrome (43223333332234).

The spelling of 21001221122222 in words is "twenty-one trillion, one billion, two hundred twenty-one million, one hundred twenty-two thousand, two hundred twenty-two".