21464320 has 72 divisors (see below), whose sum is σ = 52796520. Its totient is φ = 8355840.

The previous prime is 21464309. The next prime is 21464323. The reversal of 21464320 is 2346412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1679616 + 19784704 = 1296^2 + 4448^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21464291 and 21464300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21464323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52276 + ... + 52684.

It is an arithmetic number, because the mean of its divisors is an integer number (733285).

Almost surely, 2^21464320 is an apocalyptic number.

21464320 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 21464320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26398260).

21464320 is an abundant number, since it is smaller than the sum of its proper divisors (31332200).

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

21464320 is an equidigital number, since it uses as much as digits as its factorization.

21464320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471 (or 457 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 21464320 is about 4632.9601768200. The cubic root of 21464320 is about 277.9109836972.

The spelling of 21464320 in words is "twenty-one million, four hundred sixty-four thousand, three hundred twenty".