638320801 has 4 divisors (see below), whose sum is σ = 638482500. Its totient is φ = 638159104.

The previous prime is 638320757. The next prime is 638320807. The reversal of 638320801 is 108023836.

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 155376225 + 482944576 = 12465^2 + 21976^2 .

It is a cyclic number.

It is not a de Polignac number, because 638320801 - 2⁹ = 638320289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638320807) 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, 74776 + ... + 82873.

It is an arithmetic number, because the mean of its divisors is an integer number (159620625).

Almost surely, 2^638320801 is an apocalyptic number.

It is an amenable number.

638320801 is a deficient number, since it is larger than the sum of its proper divisors (161699).

638320801 is a wasteful number, since it uses less digits than its factorization.

638320801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161698.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 638320801 is about 25265.0113991662. The cubic root of 638320801 is about 861.0195232634.

The spelling of 638320801 in words is "six hundred thirty-eight million, three hundred twenty thousand, eight hundred one".