636403213 has 2 divisors, whose sum is σ = 636403214. Its totient is φ = 636403212.

The previous prime is 636403199. The next prime is 636403217. The reversal of 636403213 is 312304636.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 630361449 + 6041764 = 25107^2 + 2458^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-636403213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636403217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318201606 + 318201607.

It is an arithmetic number, because the mean of its divisors is an integer number (318201607).

Almost surely, 2^636403213 is an apocalyptic number.

It is an amenable number.

636403213 is a deficient number, since it is larger than the sum of its proper divisors (1).

636403213 is an equidigital number, since it uses as much as digits as its factorization.

636403213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 28.

The square root of 636403213 is about 25227.0333769153. The cubic root of 636403213 is about 860.1564583738.

Adding to 636403213 its reverse (312304636), we get a palindrome (948707849).

The spelling of 636403213 in words is "six hundred thirty-six million, four hundred three thousand, two hundred thirteen".