638611728241 has 4 divisors (see below), whose sum is σ = 638613354484. Its totient is φ = 638610102000.

The previous prime is 638611728239. The next prime is 638611728247. The reversal of 638611728241 is 142827116836.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 60563241216 + 578048487025 = 246096^2 + 760295^2 .

It is a cyclic number.

It is not a de Polignac number, because 638611728241 - 2¹ = 638611728239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638611728247) by changing a digit.

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, 181291 + ... + 1144591.

It is an arithmetic number, because the mean of its divisors is an integer number (159653338621).

Almost surely, 2^638611728241 is an apocalyptic number.

It is an amenable number.

638611728241 is a deficient number, since it is larger than the sum of its proper divisors (1626243).

638611728241 is an equidigital number, since it uses as much as digits as its factorization.

638611728241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1626242.

The product of its digits is 774144, while the sum is 49.

The spelling of 638611728241 in words is "six hundred thirty-eight billion, six hundred eleven million, seven hundred twenty-eight thousand, two hundred forty-one".