19619813209 has 2 divisors, whose sum is σ = 19619813210. Its totient is φ = 19619813208.

The previous prime is 19619813201. The next prime is 19619813243. The reversal of 19619813209 is 90231891691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10604880400 + 9014932809 = 102980^2 + 94947^2 .

It is a cyclic number.

It is not a de Polignac number, because 19619813209 - 2³ = 19619813201 is a prime.

It is not a weakly prime, because it can be changed into another prime (19619813201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9809906604 + 9809906605.

It is an arithmetic number, because the mean of its divisors is an integer number (9809906605).

Almost surely, 2^19619813209 is an apocalyptic number.

It is an amenable number.

19619813209 is a deficient number, since it is larger than the sum of its proper divisors (1).

19619813209 is an equidigital number, since it uses as much as digits as its factorization.

19619813209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 209952, while the sum is 49.

The spelling of 19619813209 in words is "nineteen billion, six hundred nineteen million, eight hundred thirteen thousand, two hundred nine".