638687322050 has 18 divisors (see below), whose sum is σ = 1187968930059. Its totient is φ = 255472668400.

The previous prime is 638687321969. The next prime is 638687322059. The reversal of 638687322050 is 50223786836.

It can be written as a sum of positive squares in 5 ways, for example, as 399048680209 + 239638641841 = 631703^2 + 489529^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=565105.

It is a Harshad number since it is a multiple of its sum of digits (50).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638687322050.

It is not an unprimeable number, because it can be changed into a prime (638687322059) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5594540 + ... + 5707560.

Almost surely, 2^638687322050 is an apocalyptic number.

638687322050 is a deficient number, since it is larger than the sum of its proper divisors (549281608009).

638687322050 is an frugal number, since it uses more digits than its factorization.

638687322050 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226054 (or 113028 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 50.

Multiplying 638687322050 by its sum of digits (50), we get a square (31934366102500 = 5651050²).

638687322050 divided by its sum of digits (50) gives a square (12773746441 = 113021²).

The spelling of 638687322050 in words is "six hundred thirty-eight billion, six hundred eighty-seven million, three hundred twenty-two thousand, fifty".