20131109 has 2 divisors, whose sum is σ = 20131110. Its totient is φ = 20131108.

The previous prime is 20131103. The next prime is 20131117. The reversal of 20131109 is 90113102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18576100 + 1555009 = 4310^2 + 1247^2 .

It is a cyclic number.

It is not a de Polignac number, because 20131109 - 2⁴ = 20131093 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20131103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10065554 + 10065555.

It is an arithmetic number, because the mean of its divisors is an integer number (10065555).

Almost surely, 2^20131109 is an apocalyptic number.

It is an amenable number.

20131109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20131109 is an equidigital number, since it uses as much as digits as its factorization.

20131109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54, while the sum is 17.

The square root of 20131109 is about 4486.7704420886. The cubic root of 20131109 is about 272.0336112228.

The spelling of 20131109 in words is "twenty million, one hundred thirty-one thousand, one hundred nine".