638396478268 has 12 divisors (see below), whose sum is σ = 1117200529312. Its totient is φ = 319196327040.

The previous prime is 638396478259. The next prime is 638396478337. The reversal of 638396478268 is 862874693836.

It is a junction number, because it is equal to n+sod(n) for n = 638396478197 and 638396478206.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 491821 + ... + 1232347.

Almost surely, 2^638396478268 is an apocalyptic number.

It is an amenable number.

638396478268 is a deficient number, since it is larger than the sum of its proper divisors (478804051044).

638396478268 is a wasteful number, since it uses less digits than its factorization.

638396478268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 956052 (or 956050 counting only the distinct ones).

The product of its digits is 501645312, while the sum is 70.

The spelling of 638396478268 in words is "six hundred thirty-eight billion, three hundred ninety-six million, four hundred seventy-eight thousand, two hundred sixty-eight".