20123211111 has 4 divisors (see below), whose sum is σ = 26830948152. Its totient is φ = 13415474072.

The previous prime is 20123211103. The next prime is 20123211181. The reversal of 20123211111 is 11111232102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20123211111 - 2³ = 20123211103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20123211181) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3353868516 + ... + 3353868521.

It is an arithmetic number, because the mean of its divisors is an integer number (6707737038).

Almost surely, 2^20123211111 is an apocalyptic number.

20123211111 is a deficient number, since it is larger than the sum of its proper divisors (6707737041).

20123211111 is an equidigital number, since it uses as much as digits as its factorization.

20123211111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6707737040.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 20123211111 its reverse (11111232102), we get a palindrome (31234443213).

It can be divided in two parts, 2012 and 3211111, that added together give a palindrome (3213123).

The spelling of 20123211111 in words is "twenty billion, one hundred twenty-three million, two hundred eleven thousand, one hundred eleven".