21364608 has 128 divisors (see below), whose sum is σ = 61689600. Its totient is φ = 6533120.

The previous prime is 21364601. The next prime is 21364627. The reversal of 21364608 is 80646312.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21364601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 362083 + ... + 362141.

It is an arithmetic number, because the mean of its divisors is an integer number (481950).

Almost surely, 2^21364608 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21364608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30844800).

21364608 is an abundant number, since it is smaller than the sum of its proper divisors (40324992).

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

21364608 is a wasteful number, since it uses less digits than its factorization.

21364608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140 (or 128 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 21364608 is about 4622.1864955884. The cubic root of 21364608 is about 277.4799725827.

The spelling of 21364608 in words is "twenty-one million, three hundred sixty-four thousand, six hundred eight".