19731091613 has 2 divisors, whose sum is σ = 19731091614. Its totient is φ = 19731091612.

The previous prime is 19731091609. The next prime is 19731091663. The reversal of 19731091613 is 31619013791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14622130084 + 5108961529 = 120922^2 + 71477^2 .

It is a cyclic number.

It is not a de Polignac number, because 19731091613 - 2² = 19731091609 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 (19731091663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9865545806 + 9865545807.

It is an arithmetic number, because the mean of its divisors is an integer number (9865545807).

Almost surely, 2^19731091613 is an apocalyptic number.

It is an amenable number.

19731091613 is a deficient number, since it is larger than the sum of its proper divisors (1).

19731091613 is an equidigital number, since it uses as much as digits as its factorization.

19731091613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30618, while the sum is 41.

The spelling of 19731091613 in words is "nineteen billion, seven hundred thirty-one million, ninety-one thousand, six hundred thirteen".