19858782817 has 2 divisors, whose sum is σ = 19858782818. Its totient is φ = 19858782816.

The previous prime is 19858782761. The next prime is 19858782841. The reversal of 19858782817 is 71828785891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15813314001 + 4045468816 = 125751^2 + 63604^2 .

It is a cyclic number.

It is not a de Polignac number, because 19858782817 - 2²⁷ = 19724565089 is a prime.

It is not a weakly prime, because it can be changed into another prime (19858782847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9929391408 + 9929391409.

It is an arithmetic number, because the mean of its divisors is an integer number (9929391409).

Almost surely, 2^19858782817 is an apocalyptic number.

It is an amenable number.

19858782817 is a deficient number, since it is larger than the sum of its proper divisors (1).

19858782817 is an equidigital number, since it uses as much as digits as its factorization.

19858782817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18063360, while the sum is 64.

The spelling of 19858782817 in words is "nineteen billion, eight hundred fifty-eight million, seven hundred eighty-two thousand, eight hundred seventeen".