20131231123111 has 4 divisors (see below), whose sum is σ = 20131576112872. Its totient is φ = 20130886133352.

The previous prime is 20131231123099. The next prime is 20131231123117. The reversal of 20131231123111 is 11132113213102.

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 20131231123111 - 2¹³ = 20131231114919 is a prime.

It is a super-2 number, since 2×20131231123111² (a number of 27 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 (20131231123117) 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, 172407336 + ... + 172524061.

It is an arithmetic number, because the mean of its divisors is an integer number (5032894028218).

Almost surely, 2^{20131231123111} is an apocalyptic number.

20131231123111 is a deficient number, since it is larger than the sum of its proper divisors (344989761).

20131231123111 is an equidigital number, since it uses as much as digits as its factorization.

20131231123111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344989760.

The product of its (nonzero) digits is 216, while the sum is 22.

Adding to 20131231123111 its reverse (11132113213102), we get a palindrome (31263344336213).

The spelling of 20131231123111 in words is "twenty trillion, one hundred thirty-one billion, two hundred thirty-one million, one hundred twenty-three thousand, one hundred eleven".