638927099989 has 2 divisors, whose sum is σ = 638927099990. Its totient is φ = 638927099988.

The previous prime is 638927099983. The next prime is 638927100023. The reversal of 638927099989 is 989990729836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 514641238225 + 124285861764 = 717385^2 + 352542^2 .

It is a cyclic number.

It is not a de Polignac number, because 638927099989 - 2⁹ = 638927099477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638927099983) 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, 319463549994 + 319463549995.

It is an arithmetic number, because the mean of its divisors is an integer number (319463549995).

Almost surely, 2^638927099989 is an apocalyptic number.

It is an amenable number.

638927099989 is a deficient number, since it is larger than the sum of its proper divisors (1).

638927099989 is an equidigital number, since it uses as much as digits as its factorization.

638927099989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 952342272, while the sum is 79.

The spelling of 638927099989 in words is "six hundred thirty-eight billion, nine hundred twenty-seven million, ninety-nine thousand, nine hundred eighty-nine".