638634334687 has 2 divisors, whose sum is σ = 638634334688. Its totient is φ = 638634334686.

The previous prime is 638634334633. The next prime is 638634334711. The reversal of 638634334687 is 786433436836.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638634334687 is a prime.

It is a super-2 number, since 2×638634334687² (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 (638634334607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319317167343 + 319317167344.

It is an arithmetic number, because the mean of its divisors is an integer number (319317167344).

Almost surely, 2^638634334687 is an apocalyptic number.

638634334687 is a deficient number, since it is larger than the sum of its proper divisors (1).

638634334687 is an equidigital number, since it uses as much as digits as its factorization.

638634334687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 125411328, while the sum is 61.

The spelling of 638634334687 in words is "six hundred thirty-eight billion, six hundred thirty-four million, three hundred thirty-four thousand, six hundred eighty-seven".