1638753203449 has 2 divisors, whose sum is σ = 1638753203450. Its totient is φ = 1638753203448.

The previous prime is 1638753203443. The next prime is 1638753203497. The reversal of 1638753203449 is 9443023578361.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 850443618025 + 788309585424 = 922195^2 + 887868^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638753203449 - 2¹¹ = 1638753201401 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1638753203449.

It is not a weakly prime, because it can be changed into another prime (1638753203443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819376601724 + 819376601725.

It is an arithmetic number, because the mean of its divisors is an integer number (819376601725).

It is a 1-persistent number, because it is pandigital, but 2⋅1638753203449 = 3277506406898 is not.

Almost surely, 2^{1638753203449} is an apocalyptic number.

It is an amenable number.

1638753203449 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638753203449 is an equidigital number, since it uses as much as digits as its factorization.

1638753203449 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13063680, while the sum is 55.

The spelling of 1638753203449 in words is "one trillion, six hundred thirty-eight billion, seven hundred fifty-three million, two hundred three thousand, four hundred forty-nine".