638378312850 has 72 divisors (see below), whose sum is σ = 1723816114020. Its totient is φ = 169370060160.

The previous prime is 638378312833. The next prime is 638378312879. The reversal of 638378312850 is 58213873836.

It can be written as a sum of positive squares in 6 ways, for example, as 494578847169 + 143799465681 = 703263^2 + 379209^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3511905 + ... + 3689204.

Almost surely, 2^638378312850 is an apocalyptic number.

638378312850 is an abundant number, since it is smaller than the sum of its proper divisors (1085437801170).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638378312850 is a wasteful number, since it uses less digits than its factorization.

638378312850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7201324 (or 7201316 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The spelling of 638378312850 in words is "six hundred thirty-eight billion, three hundred seventy-eight million, three hundred twelve thousand, eight hundred fifty".