20001212122221 has 48 divisors (see below), whose sum is σ = 32016114232128. Its totient is φ = 11930327481600.

The previous prime is 20001212122201. The next prime is 20001212122223. The reversal of 20001212122221 is 12222121210002.

It is a happy number.

20001212122221 is a `hidden beast` number, since 200 + 0 + 121 + 2 + 122 + 221 = 666.

It is not a de Polignac number, because 20001212122221 - 2¹³ = 20001212114029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20001212122194 and 20001212122203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001212122223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6059281 + ... + 8758841.

It is an arithmetic number, because the mean of its divisors is an integer number (667002379836).

Almost surely, 2^{20001212122221} is an apocalyptic number.

It is an amenable number.

20001212122221 is a deficient number, since it is larger than the sum of its proper divisors (12014902109907).

20001212122221 is a wasteful number, since it uses less digits than its factorization.

20001212122221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2700762 (or 2700759 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 20001212122221 its reverse (12222121210002), we get a palindrome (32223333332223).

The spelling of 20001212122221 in words is "twenty trillion, one billion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty-one".