638155551829 has 2 divisors, whose sum is σ = 638155551830. Its totient is φ = 638155551828.

The previous prime is 638155551823. The next prime is 638155551889. The reversal of 638155551829 is 928155551836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 377085649329 + 261069902500 = 614073^2 + 510950^2 .

It is a cyclic number.

It is not a de Polignac number, because 638155551829 - 2³¹ = 636008068181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638155551823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319077775914 + 319077775915.

It is an arithmetic number, because the mean of its divisors is an integer number (319077775915).

Almost surely, 2^638155551829 is an apocalyptic number.

It is an amenable number.

638155551829 is a deficient number, since it is larger than the sum of its proper divisors (1).

638155551829 is an equidigital number, since it uses as much as digits as its factorization.

638155551829 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960000, while the sum is 58.

The spelling of 638155551829 in words is "six hundred thirty-eight billion, one hundred fifty-five million, five hundred fifty-one thousand, eight hundred twenty-nine".