636340109 has 2 divisors, whose sum is σ = 636340110. Its totient is φ = 636340108.

The previous prime is 636340087. The next prime is 636340139. The reversal of 636340109 is 901043636.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 563920009 + 72420100 = 23747^2 + 8510^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-636340109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636340139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318170054 + 318170055.

It is an arithmetic number, because the mean of its divisors is an integer number (318170055).

Almost surely, 2^636340109 is an apocalyptic number.

It is an amenable number.

636340109 is a deficient number, since it is larger than the sum of its proper divisors (1).

636340109 is an equidigital number, since it uses as much as digits as its factorization.

636340109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 32.

The square root of 636340109 is about 25225.7826241328. The cubic root of 636340109 is about 860.1280271810.

The spelling of 636340109 in words is "six hundred thirty-six million, three hundred forty thousand, one hundred nine".