20001221120221 has 12 divisors (see below), whose sum is σ = 21990355749376. Its totient is φ = 18178344308520.

The previous prime is 20001221120201. The next prime is 20001221120281. The reversal of 20001221120221 is 12202112210002.

It is a happy number.

It is not a de Polignac number, because 20001221120221 - 2⁹ = 20001221119709 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20001221120195 and 20001221120204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001221120201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20354295 + ... + 21314308.

Almost surely, 2^{20001221120221} is an apocalyptic number.

It is an amenable number.

20001221120221 is a deficient number, since it is larger than the sum of its proper divisors (1989134629155).

20001221120221 is a wasteful number, since it uses less digits than its factorization.

20001221120221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41672592 (or 41672581 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 20001221120221 its reverse (12202112210002), we get a palindrome (32203333330223).

The spelling of 20001221120221 in words is "twenty trillion, one billion, two hundred twenty-one million, one hundred twenty thousand, two hundred twenty-one".