21564480 has 112 divisors (see below), whose sum is σ = 78272640. Its totient is φ = 4927488.

The previous prime is 21564463. The next prime is 21564497. The reversal of 21564480 is 8446512.

It is an interprime number because it is at equal distance from previous prime (21564463) and next prime (21564497).

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5116 + ... + 8324.

Almost surely, 2^21564480 is an apocalyptic number.

21564480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21564480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39136320).

21564480 is an abundant number, since it is smaller than the sum of its proper divisors (56708160).

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

21564480 is a wasteful number, since it uses less digits than its factorization.

21564480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3236 (or 3226 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 21564480 is about 4643.7570995908. The cubic root of 21564480 is about 278.3425895623.

The spelling of 21564480 in words is "twenty-one million, five hundred sixty-four thousand, four hundred eighty".