638918191853 has 8 divisors (see below), whose sum is σ = 655013345280. Its totient is φ = 622847409120.

The previous prime is 638918191841. The next prime is 638918191861. The reversal of 638918191853 is 358191819836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638918191853 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 (638918791853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6039575 + ... + 6144452.

It is an arithmetic number, because the mean of its divisors is an integer number (81876668160).

Almost surely, 2^638918191853 is an apocalyptic number.

It is an amenable number.

638918191853 is a deficient number, since it is larger than the sum of its proper divisors (16095153427).

638918191853 is a wasteful number, since it uses less digits than its factorization.

638918191853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12185347.

The product of its digits is 11197440, while the sum is 62.

The spelling of 638918191853 in words is "six hundred thirty-eight billion, nine hundred eighteen million, one hundred ninety-one thousand, eight hundred fifty-three".