19965856213 has 2 divisors, whose sum is σ = 19965856214. Its totient is φ = 19965856212.

The previous prime is 19965856201. The next prime is 19965856217. The reversal of 19965856213 is 31265856991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10766552644 + 9199303569 = 103762^2 + 95913^2 .

It is an emirp because it is prime and its reverse (31265856991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19965856213 - 2⁵ = 19965856181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19965856217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9982928106 + 9982928107.

It is an arithmetic number, because the mean of its divisors is an integer number (9982928107).

Almost surely, 2^19965856213 is an apocalyptic number.

It is an amenable number.

19965856213 is a deficient number, since it is larger than the sum of its proper divisors (1).

19965856213 is an equidigital number, since it uses as much as digits as its factorization.

19965856213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3499200, while the sum is 55.

The spelling of 19965856213 in words is "nineteen billion, nine hundred sixty-five million, eight hundred fifty-six thousand, two hundred thirteen".