638405164013 has 2 divisors, whose sum is σ = 638405164014. Its totient is φ = 638405164012.

The previous prime is 638405163983. The next prime is 638405164021. The reversal of 638405164013 is 310461504836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 624002043844 + 14403120169 = 789938^2 + 120013^2 .

It is a cyclic number.

It is not a de Polignac number, because 638405164013 - 2²⁶ = 638338055149 is a prime.

It is a super-2 number, since 2×638405164013² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638405164613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319202582006 + 319202582007.

It is an arithmetic number, because the mean of its divisors is an integer number (319202582007).

Almost surely, 2^638405164013 is an apocalyptic number.

It is an amenable number.

638405164013 is a deficient number, since it is larger than the sum of its proper divisors (1).

638405164013 is an equidigital number, since it uses as much as digits as its factorization.

638405164013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 207360, while the sum is 41.

Adding to 638405164013 its reverse (310461504836), we get a palindrome (948866668849).

The spelling of 638405164013 in words is "six hundred thirty-eight billion, four hundred five million, one hundred sixty-four thousand, thirteen".