638817201 has 18 divisors (see below), whose sum is σ = 1014248690. Its totient is φ = 387161280.

The previous prime is 638817199. The next prime is 638817209. The reversal of 638817201 is 102718836.

638817201 is a `hidden beast` number, since 638 + 8 + 17 + 2 + 0 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 617472801 + 21344400 = 24849^2 + 4620^2 .

It is not a de Polignac number, because 638817201 - 2¹ = 638817199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638817209) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 292216 + ... + 294393.

Almost surely, 2^638817201 is an apocalyptic number.

It is an amenable number.

638817201 is a deficient number, since it is larger than the sum of its proper divisors (375431489).

638817201 is a wasteful number, since it uses less digits than its factorization.

638817201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586637 (or 586623 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 638817201 is about 25274.8333525663. The cubic root of 638817201 is about 861.2426604616.

The spelling of 638817201 in words is "six hundred thirty-eight million, eight hundred seventeen thousand, two hundred one".