20131423561 has 2 divisors, whose sum is σ = 20131423562. Its totient is φ = 20131423560.

The previous prime is 20131423537. The next prime is 20131423577. The reversal of 20131423561 is 16532413102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15455462400 + 4675961161 = 124320^2 + 68381^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20131423561 is a prime.

It is not a weakly prime, because it can be changed into another prime (20131423061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10065711780 + 10065711781.

It is an arithmetic number, because the mean of its divisors is an integer number (10065711781).

Almost surely, 2^20131423561 is an apocalyptic number.

It is an amenable number.

20131423561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20131423561 is an equidigital number, since it uses as much as digits as its factorization.

20131423561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 20131423561 its reverse (16532413102), we get a palindrome (36663836663).

The spelling of 20131423561 in words is "twenty billion, one hundred thirty-one million, four hundred twenty-three thousand, five hundred sixty-one".