20121121111 has 16 divisors (see below), whose sum is σ = 24768433984. Its totient is φ = 15917451264.

The previous prime is 20121121067. The next prime is 20121121151. The reversal of 20121121111 is 11112112102.

It is a happy number.

It is not a de Polignac number, because 20121121111 - 2⁷ = 20121120983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a junction number, because it is equal to n+sod(n) for n = 20121121091 and 20121121100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121121151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 719095 + ... + 746551.

It is an arithmetic number, because the mean of its divisors is an integer number (1548027124).

Almost surely, 2^20121121111 is an apocalyptic number.

20121121111 is a deficient number, since it is larger than the sum of its proper divisors (4647312873).

20121121111 is a wasteful number, since it uses less digits than its factorization.

20121121111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35530.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 20121121111 its reverse (11112112102), we get a palindrome (31233233213).

Subtracting from 20121121111 its reverse (11112112102), we obtain a palindrome (9009009009).

The spelling of 20121121111 in words is "twenty billion, one hundred twenty-one million, one hundred twenty-one thousand, one hundred eleven".