20211211111 has 16 divisors (see below), whose sum is σ = 24892619584. Its totient is φ = 15980177664.

The previous prime is 20211211109. The next prime is 20211211117. The reversal of 20211211111 is 11111211202.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20211211111 - 2¹ = 20211211109 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 = 20211211091 and 20211211100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211211117) 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, 55795 + ... + 208651.

It is an arithmetic number, because the mean of its divisors is an integer number (1555788724).

Almost surely, 2^20211211111 is an apocalyptic number.

20211211111 is a deficient number, since it is larger than the sum of its proper divisors (4681408473).

20211211111 is a wasteful number, since it uses less digits than its factorization.

20211211111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154330.

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

Adding to 20211211111 its reverse (11111211202), we get a palindrome (31322422313).

Subtracting from 20211211111 its reverse (11111211202), we obtain a palindrome (9099999909).

The spelling of 20211211111 in words is "twenty billion, two hundred eleven million, two hundred eleven thousand, one hundred eleven".