636381394 has 16 divisors (see below), whose sum is σ = 1077261120. Its totient is φ = 279289360.

The previous prime is 636381373. The next prime is 636381407. The reversal of 636381394 is 493183636.

It is a self number, because there is not a number n which added to its sum of digits gives 636381394.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 498094 + ... + 499369.

It is an arithmetic number, because the mean of its divisors is an integer number (67328820).

Almost surely, 2^636381394 is an apocalyptic number.

636381394 is a deficient number, since it is larger than the sum of its proper divisors (440879726).

636381394 is a wasteful number, since it uses less digits than its factorization.

636381394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997505.

The product of its digits is 279936, while the sum is 43.

The square root of 636381394 is about 25226.6009204570. The cubic root of 636381394 is about 860.1466281446.

The spelling of 636381394 in words is "six hundred thirty-six million, three hundred eighty-one thousand, three hundred ninety-four".