19807663493 has 2 divisors, whose sum is σ = 19807663494. Its totient is φ = 19807663492.

The previous prime is 19807663483. The next prime is 19807663501. The reversal of 19807663493 is 39436670891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19735192324 + 72471169 = 140482^2 + 8513^2 .

It is an emirp because it is prime and its reverse (39436670891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19807663493 - 2¹⁴ = 19807647109 is a prime.

It is a super-2 number, since 2×19807663493² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19807663453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9903831746 + 9903831747.

It is an arithmetic number, because the mean of its divisors is an integer number (9903831747).

Almost surely, 2^19807663493 is an apocalyptic number.

It is an amenable number.

19807663493 is a deficient number, since it is larger than the sum of its proper divisors (1).

19807663493 is an equidigital number, since it uses as much as digits as its factorization.

19807663493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5878656, while the sum is 56.

The spelling of 19807663493 in words is "nineteen billion, eight hundred seven million, six hundred sixty-three thousand, four hundred ninety-three".