20121221121111 has 32 divisors (see below), whose sum is σ = 32654079575040. Its totient is φ = 12144079094400.

The previous prime is 20121221121083. The next prime is 20121221121121. The reversal of 20121221121111 is 11112112212102.

It is a happy number.

20121221121111 is a `hidden beast` number, since 20 + 1 + 212 + 211 + 211 + 11 = 666.

It is not a de Polignac number, because 20121221121111 - 2¹⁵ = 20121221088343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121221121121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 140484895 + ... + 140628048.

It is an arithmetic number, because the mean of its divisors is an integer number (1020439986720).

Almost surely, 2^{20121221121111} is an apocalyptic number.

20121221121111 is a deficient number, since it is larger than the sum of its proper divisors (12532858453929).

20121221121111 is a wasteful number, since it uses less digits than its factorization.

20121221121111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281113204 (or 281113198 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 20121221121111 its reverse (11112112212102), we get a palindrome (31233333333213).

The spelling of 20121221121111 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty-one million, one hundred twenty-one thousand, one hundred eleven".