636642001 has 4 divisors (see below), whose sum is σ = 664322112. Its totient is φ = 608961892.

The previous prime is 636641963. The next prime is 636642007. The reversal of 636642001 is 100246636.

636642001 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 636642001 - 2²³ = 628253393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636642007) 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, 13840021 + ... + 13840066.

It is an arithmetic number, because the mean of its divisors is an integer number (166080528).

Almost surely, 2^636642001 is an apocalyptic number.

It is an amenable number.

636642001 is a deficient number, since it is larger than the sum of its proper divisors (27680111).

636642001 is a wasteful number, since it uses less digits than its factorization.

636642001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27680110.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 636642001 is about 25231.7657130848. The cubic root of 636642001 is about 860.2640261089.

Adding to 636642001 its reverse (100246636), we get a palindrome (736888637).

The spelling of 636642001 in words is "six hundred thirty-six million, six hundred forty-two thousand, one".