21320448 has 144 divisors (see below), whose sum is σ = 63576576. Its totient is φ = 6307840.

The previous prime is 21320447. The next prime is 21320479. The reversal of 21320448 is 84402312.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21320447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 300253 + ... + 300323.

It is an arithmetic number, because the mean of its divisors is an integer number (441504).

Almost surely, 2^21320448 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 21320448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31788288).

21320448 is an abundant number, since it is smaller than the sum of its proper divisors (42256128).

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

21320448 is a wasteful number, since it uses less digits than its factorization.

21320448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 21320448 is about 4617.4070645764. The cubic root of 21320448 is about 277.2886597997.

The spelling of 21320448 in words is "twenty-one million, three hundred twenty thousand, four hundred forty-eight".