8721638201 has 4 divisors (see below), whose sum is σ = 8721826932. Its totient is φ = 8721449472.

The previous prime is 8721638179. The next prime is 8721638273. The reversal of 8721638201 is 1028361278.

8721638201 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 4089474601 + 4632163600 = 63949^2 + 68060^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8721638201 is a prime.

It is a super-5 number, since 5×8721638201⁵ (a number of 51 digits) contains 55555 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8721637201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26885 + ... + 134781.

It is an arithmetic number, because the mean of its divisors is an integer number (2180456733).

Almost surely, 2^8721638201 is an apocalyptic number.

It is an amenable number.

8721638201 is a deficient number, since it is larger than the sum of its proper divisors (188731).

8721638201 is a wasteful number, since it uses less digits than its factorization.

8721638201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188730.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 8721638201 is about 93389.7114301142. The cubic root of 8721638201 is about 2058.4138197371.

Adding to 8721638201 its reverse (1028361278), we get a palindrome (9749999479).

The spelling of 8721638201 in words is "eight billion, seven hundred twenty-one million, six hundred thirty-eight thousand, two hundred one".