20131123109 has 2 divisors, whose sum is σ = 20131123110. Its totient is φ = 20131123108.

The previous prime is 20131123099. The next prime is 20131123147. The reversal of 20131123109 is 90132113102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10847222500 + 9283900609 = 104150^2 + 96353^2 .

It is a cyclic number.

It is not a de Polignac number, because 20131123109 - 2²⁸ = 19862687653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20131123009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10065561554 + 10065561555.

It is an arithmetic number, because the mean of its divisors is an integer number (10065561555).

Almost surely, 2^20131123109 is an apocalyptic number.

It is an amenable number.

20131123109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20131123109 is an equidigital number, since it uses as much as digits as its factorization.

20131123109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 23.

The spelling of 20131123109 in words is "twenty billion, one hundred thirty-one million, one hundred twenty-three thousand, one hundred nine".