638828807 has 4 divisors (see below), whose sum is σ = 640130376. Its totient is φ = 637527240.

The previous prime is 638828789. The next prime is 638828867. The reversal of 638828807 is 708828836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 638828807 - 2¹⁶ = 638763271 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638828867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 650048 + ... + 651029.

It is an arithmetic number, because the mean of its divisors is an integer number (160032594).

Almost surely, 2^638828807 is an apocalyptic number.

638828807 is a deficient number, since it is larger than the sum of its proper divisors (1301569).

638828807 is a wasteful number, since it uses less digits than its factorization.

638828807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1301568.

The product of its (nonzero) digits is 1032192, while the sum is 50.

The square root of 638828807 is about 25275.0629474983. The cubic root of 638828807 is about 861.2478761016.

The spelling of 638828807 in words is "six hundred thirty-eight million, eight hundred twenty-eight thousand, eight hundred seven".