636220061 has 4 divisors (see below), whose sum is σ = 639516732. Its totient is φ = 632923392.

The previous prime is 636220051. The next prime is 636220093. The reversal of 636220061 is 160022636.

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

It can be written as a sum of positive squares in 2 ways, for example, as 315595225 + 320624836 = 17765^2 + 17906^2 .

It is a cyclic number.

It is not a de Polignac number, because 636220061 - 2¹⁰ = 636219037 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 636220061.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636220031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1648046 + ... + 1648431.

It is an arithmetic number, because the mean of its divisors is an integer number (159879183).

Almost surely, 2^636220061 is an apocalyptic number.

It is an amenable number.

636220061 is a deficient number, since it is larger than the sum of its proper divisors (3296671).

636220061 is a wasteful number, since it uses less digits than its factorization.

636220061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3296670.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 636220061 is about 25223.4030416199. The cubic root of 636220061 is about 860.0739349632.

Adding to 636220061 its reverse (160022636), we get a palindrome (796242697).

The spelling of 636220061 in words is "six hundred thirty-six million, two hundred twenty thousand, sixty-one".