19438218493 has 2 divisors, whose sum is σ = 19438218494. Its totient is φ = 19438218492.

The previous prime is 19438218463. The next prime is 19438218497. The reversal of 19438218493 is 39481283491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19431802404 + 6416089 = 139398^2 + 2533^2 .

It is a cyclic number.

It is not a de Polignac number, because 19438218493 - 2¹³ = 19438210301 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19438218493.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19438218497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9719109246 + 9719109247.

It is an arithmetic number, because the mean of its divisors is an integer number (9719109247).

Almost surely, 2^19438218493 is an apocalyptic number.

It is an amenable number.

19438218493 is a deficient number, since it is larger than the sum of its proper divisors (1).

19438218493 is an equidigital number, since it uses as much as digits as its factorization.

19438218493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1492992, while the sum is 52.

The spelling of 19438218493 in words is "nineteen billion, four hundred thirty-eight million, two hundred eighteen thousand, four hundred ninety-three".