636056721 has 6 divisors (see below), whose sum is σ = 918748610. Its totient is φ = 424037808.

The previous prime is 636056719. The next prime is 636056761. The reversal of 636056721 is 127650636.

636056721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 503553600 + 132503121 = 22440^2 + 11511^2 .

It is not a de Polignac number, because 636056721 - 2¹ = 636056719 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (636056761) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35336476 + ... + 35336493.

Almost surely, 2^636056721 is an apocalyptic number.

It is an amenable number.

636056721 is a deficient number, since it is larger than the sum of its proper divisors (282691889).

636056721 is a wasteful number, since it uses less digits than its factorization.

636056721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70672975 (or 70672972 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The square root of 636056721 is about 25220.1649677396. The cubic root of 636056721 is about 860.0003249503. Note that the first 3 decimals are identical.

The spelling of 636056721 in words is "six hundred thirty-six million, fifty-six thousand, seven hundred twenty-one".