1638115474109 has 2 divisors, whose sum is σ = 1638115474110. Its totient is φ = 1638115474108.

The previous prime is 1638115474063. The next prime is 1638115474139. The reversal of 1638115474109 is 9014745118361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1436649151609 + 201466322500 = 1198603^2 + 448850^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638115474109 - 2³⁶ = 1569395997373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1638115474139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819057737054 + 819057737055.

It is an arithmetic number, because the mean of its divisors is an integer number (819057737055).

Almost surely, 2^{1638115474109} is an apocalyptic number.

It is an amenable number.

1638115474109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638115474109 is an equidigital number, since it uses as much as digits as its factorization.

1638115474109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 725760, while the sum is 50.

The spelling of 1638115474109 in words is "one trillion, six hundred thirty-eight billion, one hundred fifteen million, four hundred seventy-four thousand, one hundred nine".