638836128849 has 8 divisors (see below), whose sum is σ = 888815483712. Its totient is φ = 407373763280.

The previous prime is 638836128817. The next prime is 638836128851. The reversal of 638836128849 is 948821638836.

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

It is a cyclic number.

It is not a de Polignac number, because 638836128849 - 2⁵ = 638836128817 is a prime.

It is a super-2 number, since 2×638836128849² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 638836128849.

It is not an unprimeable number, because it can be changed into a prime (638836128649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4629247242 + ... + 4629247379.

It is an arithmetic number, because the mean of its divisors is an integer number (111101935464).

Almost surely, 2^638836128849 is an apocalyptic number.

638836128849 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

638836128849 is a deficient number, since it is larger than the sum of its proper divisors (249979354863).

638836128849 is a wasteful number, since it uses less digits than its factorization.

638836128849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9258494647.

The product of its digits is 95551488, while the sum is 66.

The spelling of 638836128849 in words is "six hundred thirty-eight billion, eight hundred thirty-six million, one hundred twenty-eight thousand, eight hundred forty-nine".