19808527493 has 2 divisors, whose sum is σ = 19808527494. Its totient is φ = 19808527492.

The previous prime is 19808527489. The next prime is 19808527547. The reversal of 19808527493 is 39472580891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19466388484 + 342139009 = 139522^2 + 18497^2 .

It is a cyclic number.

It is not a de Polignac number, because 19808527493 - 2² = 19808527489 is a prime.

It is a super-2 number, since 2×19808527493² (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 (19808527433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9904263746 + 9904263747.

It is an arithmetic number, because the mean of its divisors is an integer number (9904263747).

Almost surely, 2^19808527493 is an apocalyptic number.

It is an amenable number.

19808527493 is a deficient number, since it is larger than the sum of its proper divisors (1).

19808527493 is an equidigital number, since it uses as much as digits as its factorization.

19808527493 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4354560, while the sum is 56.

The spelling of 19808527493 in words is "nineteen billion, eight hundred eight million, five hundred twenty-seven thousand, four hundred ninety-three".