638910996587 has 2 divisors, whose sum is σ = 638910996588. Its totient is φ = 638910996586.

The previous prime is 638910996487. The next prime is 638910996593. The reversal of 638910996587 is 785699019836.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638910996587 - 2³⁶ = 570191519851 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638910996587.

It is not a weakly prime, because it can be changed into another prime (638910996487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319455498293 + 319455498294.

It is an arithmetic number, because the mean of its divisors is an integer number (319455498294).

Almost surely, 2^638910996587 is an apocalyptic number.

638910996587 is a deficient number, since it is larger than the sum of its proper divisors (1).

638910996587 is an equidigital number, since it uses as much as digits as its factorization.

638910996587 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 176359680, while the sum is 71.

The spelling of 638910996587 in words is "six hundred thirty-eight billion, nine hundred ten million, nine hundred ninety-six thousand, five hundred eighty-seven".