9921564 has 18 divisors (see below), whose sum is σ = 25079600. Its totient is φ = 3307176.

The previous prime is 9921529. The next prime is 9921577. The reversal of 9921564 is 4651299.

9921564 is a `hidden beast` number, since 9 + 92 + 1 + 564 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 275599 = 9921564 / (9 + 9 + 2 + 1 + 5 + 6 + 4).

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 137764 + ... + 137835.

Almost surely, 2^9921564 is an apocalyptic number.

It is an amenable number.

9921564 is an abundant number, since it is smaller than the sum of its proper divisors (15158036).

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

9921564 is a wasteful number, since it uses less digits than its factorization.

9921564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275609 (or 275604 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 9921564 is about 3149.8514250675. The cubic root of 9921564 is about 214.8787056957.

It can be divided in two parts, 992 and 1564, that added together give a triangular number (2556 = T₇₁).

The spelling of 9921564 in words is "nine million, nine hundred twenty-one thousand, five hundred sixty-four".