20131111 has 48 divisors (see below), whose sum is σ = 29302560. Its totient is φ = 13628160.

The previous prime is 20131109. The next prime is 20131117. The reversal of 20131111 is 11113102.

It is not a de Polignac number, because 20131111 - 2¹ = 20131109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20131117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1184175 + ... + 1184191.

It is an arithmetic number, because the mean of its divisors is an integer number (610470).

Almost surely, 2^20131111 is an apocalyptic number.

20131111 is a deficient number, since it is larger than the sum of its proper divisors (9171449).

20131111 is a wasteful number, since it uses less digits than its factorization.

20131111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81 (or 48 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 10.

The square root of 20131111 is about 4486.7706649661. The cubic root of 20131111 is about 272.0336202315.

Adding to 20131111 its reverse (11113102), we get a palindrome (31244213).

Subtracting from 20131111 its reverse (11113102), we obtain a square (9018009 = 3003²).

It can be divided in two parts, 20 and 131111, that added together give a palindrome (131131).

The spelling of 20131111 in words is "twenty million, one hundred thirty-one thousand, one hundred eleven".