8721564 has 12 divisors (see below), whose sum is σ = 20350344. Its totient is φ = 2907184.

The previous prime is 8721541. The next prime is 8721599. The reversal of 8721564 is 4651278.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 363387 + ... + 363410.

It is an arithmetic number, because the mean of its divisors is an integer number (1695862).

Almost surely, 2^8721564 is an apocalyptic number.

It is an amenable number.

8721564 is an abundant number, since it is smaller than the sum of its proper divisors (11628780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8721564 is a wasteful number, since it uses less digits than its factorization.

8721564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726804 (or 726802 counting only the distinct ones).

The product of its digits is 13440, while the sum is 33.

The square root of 8721564 is about 2953.2294187889. The cubic root of 8721564 is about 205.8407982271.

The spelling of 8721564 in words is "eight million, seven hundred twenty-one thousand, five hundred sixty-four".