8721643 has 8 divisors (see below), whose sum is σ = 10211040. Its totient is φ = 7293120.

The previous prime is 8721631. The next prime is 8721667. The reversal of 8721643 is 3461278.

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

It is a cyclic number.

It is not a de Polignac number, because 8721643 - 2¹³ = 8713451 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8721673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14908 + ... + 15481.

It is an arithmetic number, because the mean of its divisors is an integer number (1276380).

Almost surely, 2^8721643 is an apocalyptic number.

8721643 is a deficient number, since it is larger than the sum of its proper divisors (1489397).

8721643 is a wasteful number, since it uses less digits than its factorization.

8721643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30437.

The product of its digits is 8064, while the sum is 31.

The square root of 8721643 is about 2953.2427939470. The cubic root of 8721643 is about 205.8414197278.

The spelling of 8721643 in words is "eight million, seven hundred twenty-one thousand, six hundred forty-three".