20121220212111 has 24 divisors (see below), whose sum is σ = 29548389630240. Its totient is φ = 13190693630400.

The previous prime is 20121220212091. The next prime is 20121220212173. The reversal of 20121220212111 is 11121202212102.

20121220212111 is a `hidden beast` number, since 2 + 0 + 121 + 220 + 212 + 111 = 666.

It is not a de Polignac number, because 20121220212111 - 2¹⁵ = 20121220179343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121220211111) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2885760 + ... + 6969221.

It is an arithmetic number, because the mean of its divisors is an integer number (1231182901260).

Almost surely, 2^{20121220212111} is an apocalyptic number.

20121220212111 is a deficient number, since it is larger than the sum of its proper divisors (9427169418129).

20121220212111 is a wasteful number, since it uses less digits than its factorization.

20121220212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9858767 (or 9858764 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 20121220212111 its reverse (11121202212102), we get a palindrome (31242422424213).

Subtracting from 20121220212111 its reverse (11121202212102), we obtain a square (9000018000009 = 3000003²).

The spelling of 20121220212111 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty million, two hundred twelve thousand, one hundred eleven".