21221221222120 has 64 divisors (see below), whose sum is σ = 48068203475520. Its totient is φ = 8431578261504.

The previous prime is 21221221222099. The next prime is 21221221222171. The reversal of 21221221222120 is 2122212212212.

It is a junction number, because it is equal to n+sod(n) for n = 21221221222091 and 21221221222100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10458904 + ... + 12321976.

It is an arithmetic number, because the mean of its divisors is an integer number (751065679305).

Almost surely, 2^{21221221222120} is an apocalyptic number.

21221221222120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221221222120 is an abundant number, since it is smaller than the sum of its proper divisors (26846982253400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221221222120 is a wasteful number, since it uses less digits than its factorization.

21221221222120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1864994 (or 1864990 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21221221222120 its reverse (2122212212212), we get a palindrome (23343433434332).

The spelling of 21221221222120 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, one hundred twenty".