20111111231 has 4 divisors (see below), whose sum is σ = 21294117792. Its totient is φ = 18928104672.

The previous prime is 20111111227. The next prime is 20111111233. The reversal of 20111111231 is 13211111102.

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 20111111231 - 2² = 20111111227 is a prime.

It is a super-2 number, since 2×20111111231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111111233) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 591503255 + ... + 591503288.

It is an arithmetic number, because the mean of its divisors is an integer number (5323529448).

Almost surely, 2^20111111231 is an apocalyptic number.

20111111231 is a deficient number, since it is larger than the sum of its proper divisors (1183006561).

20111111231 is a wasteful number, since it uses less digits than its factorization.

20111111231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183006560.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 20111111231 its reverse (13211111102), we get a palindrome (33322222333).

The spelling of 20111111231 in words is "twenty billion, one hundred eleven million, one hundred eleven thousand, two hundred thirty-one".