638861727825 has 60 divisors (see below), whose sum is σ = 1184730243840. Its totient is φ = 340341164640.

The previous prime is 638861727787. The next prime is 638861727857. The reversal of 638861727825 is 528727168836.

638861727825 is a `hidden beast` number, since 6 + 3 + 8 + 8 + 617 + 2 + 7 + 8 + 2 + 5 = 666.

It is not a de Polignac number, because 638861727825 - 2¹⁷ = 638861596753 is a prime.

It is a super-3 number, since 3×638861727825³ (a number of 36 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1618336 + ... + 1974014.

It is an arithmetic number, because the mean of its divisors is an integer number (19745504064).

Almost surely, 2^638861727825 is an apocalyptic number.

It is an amenable number.

638861727825 is a deficient number, since it is larger than the sum of its proper divisors (545868516015).

638861727825 is a wasteful number, since it uses less digits than its factorization.

638861727825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356588 (or 356574 counting only the distinct ones).

The product of its digits is 54190080, while the sum is 63.

The spelling of 638861727825 in words is "six hundred thirty-eight billion, eight hundred sixty-one million, seven hundred twenty-seven thousand, eight hundred twenty-five".