638128249899 has 16 divisors (see below), whose sum is σ = 972469865472. Its totient is φ = 364613228928.

The previous prime is 638128249883. The next prime is 638128249939. The reversal of 638128249899 is 998942821836.

It is not a de Polignac number, because 638128249899 - 2⁴ = 638128249883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638128247899) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1061779 + ... + 1550364.

It is an arithmetic number, because the mean of its divisors is an integer number (60779366592).

Almost surely, 2^638128249899 is an apocalyptic number.

638128249899 is a deficient number, since it is larger than the sum of its proper divisors (334341615573).

638128249899 is a wasteful number, since it uses less digits than its factorization.

638128249899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2623786.

The product of its digits is 107495424, while the sum is 69.

The spelling of 638128249899 in words is "six hundred thirty-eight billion, one hundred twenty-eight million, two hundred forty-nine thousand, eight hundred ninety-nine".