638841058813 has 4 divisors (see below), whose sum is σ = 647592306268. Its totient is φ = 630089811360.

The previous prime is 638841058747. The next prime is 638841058819. The reversal of 638841058813 is 318850148836.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 305435286244 + 333405772569 = 552662^2 + 577413^2 .

It is a cyclic number.

It is not a de Polignac number, because 638841058813 - 2¹³ = 638841050621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638841058819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4375623618 + ... + 4375623763.

It is an arithmetic number, because the mean of its divisors is an integer number (161898076567).

Almost surely, 2^638841058813 is an apocalyptic number.

It is an amenable number.

638841058813 is a deficient number, since it is larger than the sum of its proper divisors (8751247455).

638841058813 is an equidigital number, since it uses as much as digits as its factorization.

638841058813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8751247454.

The product of its (nonzero) digits is 4423680, while the sum is 55.

The spelling of 638841058813 in words is "six hundred thirty-eight billion, eight hundred forty-one million, fifty-eight thousand, eight hundred thirteen".