11211220111 has 16 divisors (see below), whose sum is σ = 13813542400. Its totient is φ = 8860697568.

The previous prime is 11211220109. The next prime is 11211220147. The reversal of 11211220111 is 11102211211.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 11211220111 - 2¹ = 11211220109 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 = 11211220091 and 11211220100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11211220411) 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, 16600 + ... + 150658.

It is an arithmetic number, because the mean of its divisors is an integer number (863346400).

Almost surely, 2^11211220111 is an apocalyptic number.

11211220111 is a deficient number, since it is larger than the sum of its proper divisors (2602322289).

11211220111 is a wasteful number, since it uses less digits than its factorization.

11211220111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134998.

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

Adding to 11211220111 its reverse (11102211211), we get a palindrome (22313431322).

The spelling of 11211220111 in words is "eleven billion, two hundred eleven million, two hundred twenty thousand, one hundred eleven".