638648714025 has 405 divisors, whose sum is σ = 1433172481191. Its totient is φ = 280330787520.

The previous prime is 638648713951. The next prime is 638648714029. The reversal of 638648714025 is 520417846836.

It is a happy number.

The square root of 638648714025 is 799155.

It is a perfect power (a square), and thus also a powerful number.

638648714025 is a `hidden beast` number, since 63 + 86 + 487 + 1 + 4 + 0 + 25 = 666.

It can be written as a sum of positive squares in only one way, i.e., 229913537049 + 408735176976 = 479493^2 + 639324^2 .

It is a tau number, because it is divible by the number of its divisors (405).

It is not a de Polignac number, because 638648714025 - 2⁷ = 638648713897 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (638648714029) by changing a digit.

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 404 ways as a sum of consecutive naturals, for example, 10824554446 + ... + 10824554504.

Almost surely, 2^638648714025 is an apocalyptic number.

638648714025 is the 799155-th square number.

638648714025 is the 399578-th centered octagonal number.

It is an amenable number.

638648714025 is an abundant number, since it is smaller than the sum of its proper divisors (794523767166).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638648714025 is an equidigital number, since it uses as much as digits as its factorization.

638648714025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The spelling of 638648714025 in words is "six hundred thirty-eight billion, six hundred forty-eight million, seven hundred fourteen thousand, twenty-five".