19544420817 has 24 divisors (see below), whose sum is σ = 28772051880. Its totient is φ = 12782188800.

The previous prime is 19544420809. The next prime is 19544420837. The reversal of 19544420817 is 71802444591.

19544420817 is a `hidden beast` number, since 1 + 9 + 544 + 4 + 20 + 81 + 7 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 16354317456 + 3190103361 = 127884^2 + 56481^2 .

It is not a de Polignac number, because 19544420817 - 2³ = 19544420809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19544420837) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 453 + ... + 197709.

It is an arithmetic number, because the mean of its divisors is an integer number (1198835495).

Almost surely, 2^19544420817 is an apocalyptic number.

It is an amenable number.

19544420817 is a deficient number, since it is larger than the sum of its proper divisors (9227631063).

19544420817 is a wasteful number, since it uses less digits than its factorization.

19544420817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197473 (or 197470 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 19544420817 in words is "nineteen billion, five hundred forty-four million, four hundred twenty thousand, eight hundred seventeen".