636864493 has 2 divisors, whose sum is σ = 636864494. Its totient is φ = 636864492.

The previous prime is 636864469. The next prime is 636864499. The reversal of 636864493 is 394468636.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 494706564 + 142157929 = 22242^2 + 11923^2 .

It is a cyclic number.

It is not a de Polignac number, because 636864493 - 2²⁵ = 603310061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636864499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318432246 + 318432247.

It is an arithmetic number, because the mean of its divisors is an integer number (318432247).

Almost surely, 2^636864493 is an apocalyptic number.

It is an amenable number.

636864493 is a deficient number, since it is larger than the sum of its proper divisors (1).

636864493 is an equidigital number, since it uses as much as digits as its factorization.

636864493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2239488, while the sum is 49.

The square root of 636864493 is about 25236.1742940565. The cubic root of 636864493 is about 860.3642287193.

The spelling of 636864493 in words is "six hundred thirty-six million, eight hundred sixty-four thousand, four hundred ninety-three".