638381355371 has 4 divisors (see below), whose sum is σ = 638514384000. Its totient is φ = 638248326744.

The previous prime is 638381355343. The next prime is 638381355413. The reversal of 638381355371 is 173553183836.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 638381355371 - 2¹⁸ = 638381093227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638381355341) 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, 66507116 + ... + 66516713.

It is an arithmetic number, because the mean of its divisors is an integer number (159628596000).

Almost surely, 2^638381355371 is an apocalyptic number.

638381355371 is a deficient number, since it is larger than the sum of its proper divisors (133028629).

638381355371 is a wasteful number, since it uses less digits than its factorization.

638381355371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133028628.

The product of its digits is 5443200, while the sum is 53.

The spelling of 638381355371 in words is "six hundred thirty-eight billion, three hundred eighty-one million, three hundred fifty-five thousand, three hundred seventy-one".