19688942809 has 2 divisors, whose sum is σ = 19688942810. Its totient is φ = 19688942808.

The previous prime is 19688942783. The next prime is 19688942843. The reversal of 19688942809 is 90824988691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15490291600 + 4198651209 = 124460^2 + 64797^2 .

It is a cyclic number.

It is not a de Polignac number, because 19688942809 - 2³¹ = 17541459161 is a prime.

It is not a weakly prime, because it can be changed into another prime (19688942849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9844471404 + 9844471405.

It is an arithmetic number, because the mean of its divisors is an integer number (9844471405).

Almost surely, 2^19688942809 is an apocalyptic number.

It is an amenable number.

19688942809 is a deficient number, since it is larger than the sum of its proper divisors (1).

19688942809 is an equidigital number, since it uses as much as digits as its factorization.

19688942809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17915904, while the sum is 64.

The spelling of 19688942809 in words is "nineteen billion, six hundred eighty-eight million, nine hundred forty-two thousand, eight hundred nine".