636384891 has 4 divisors (see below), whose sum is σ = 848513192. Its totient is φ = 424256592.

The previous prime is 636384887. The next prime is 636384901. The reversal of 636384891 is 198483636.

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

It is not a de Polignac number, because 636384891 - 2² = 636384887 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 636384891.

It is not an unprimeable number, because it can be changed into a prime (636384491) 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, 106064146 + ... + 106064151.

It is an arithmetic number, because the mean of its divisors is an integer number (212128298).

Almost surely, 2^636384891 is an apocalyptic number.

636384891 is a deficient number, since it is larger than the sum of its proper divisors (212128301).

636384891 is a wasteful number, since it uses less digits than its factorization.

636384891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212128300.

The product of its digits is 746496, while the sum is 48.

The square root of 636384891 is about 25226.6702321174. The cubic root of 636384891 is about 860.1482036816.

The spelling of 636384891 in words is "six hundred thirty-six million, three hundred eighty-four thousand, eight hundred ninety-one".