638712793 has 4 divisors (see below), whose sum is σ = 641087460. Its totient is φ = 636338128.

The previous prime is 638712779. The next prime is 638712799. The reversal of 638712793 is 397217836.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 39589264 + 599123529 = 6292^2 + 24477^2 .

It is a cyclic number.

It is not a de Polignac number, because 638712793 - 2²¹ = 636615641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638712799) 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 3 ways as a sum of consecutive naturals, for example, 1186930 + ... + 1187467.

It is an arithmetic number, because the mean of its divisors is an integer number (160271865).

Almost surely, 2^638712793 is an apocalyptic number.

It is an amenable number.

638712793 is a deficient number, since it is larger than the sum of its proper divisors (2374667).

638712793 is a wasteful number, since it uses less digits than its factorization.

638712793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2374666.

The product of its digits is 381024, while the sum is 46.

The square root of 638712793 is about 25272.7678143887. The cubic root of 638712793 is about 861.1957375323.

The spelling of 638712793 in words is "six hundred thirty-eight million, seven hundred twelve thousand, seven hundred ninety-three".