8636721 has 8 divisors (see below), whose sum is σ = 11733120. Its totient is φ = 5649072.

The previous prime is 8636713. The next prime is 8636737. The reversal of 8636721 is 1276368.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 8636721 - 2³ = 8636713 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

8636721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8636701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27001 + ... + 27318.

It is an arithmetic number, because the mean of its divisors is an integer number (1466640).

Almost surely, 2^8636721 is an apocalyptic number.

It is an amenable number.

8636721 is a deficient number, since it is larger than the sum of its proper divisors (3096399).

8636721 is a wasteful number, since it uses less digits than its factorization.

8636721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54375.

The product of its digits is 12096, while the sum is 33.

The square root of 8636721 is about 2938.8298691826. The cubic root of 8636721 is about 205.1711519318.

The spelling of 8636721 in words is "eight million, six hundred thirty-six thousand, seven hundred twenty-one".