21546320 has 40 divisors (see below), whose sum is σ = 51324840. Its totient is φ = 8407040.

The previous prime is 21546313. The next prime is 21546347. The reversal of 21546320 is 2364512.

It can be written as a sum of positive squares in 4 ways, for example, as 1547536 + 19998784 = 1244^2 + 4472^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5 + ... + 6564.

It is an arithmetic number, because the mean of its divisors is an integer number (1283121).

Almost surely, 2^21546320 is an apocalyptic number.

21546320 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 21546320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25662420).

21546320 is an abundant number, since it is smaller than the sum of its proper divisors (29778520).

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

21546320 is a wasteful number, since it uses less digits than its factorization.

21546320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6623 (or 6617 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21546320 is about 4641.8013744666. The cubic root of 21546320 is about 278.2644344822.

The spelling of 21546320 in words is "twenty-one million, five hundred forty-six thousand, three hundred twenty".