21228480 has 392 divisors, whose sum is σ = 93280992. Its totient is φ = 4478976.

The previous prime is 21228469. The next prime is 21228509. The reversal of 21228480 is 8482212.

It is a super-2 number, since 2×21228480² = 901296726220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 4.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 1632954 + ... + 1632966.

Almost surely, 2^21228480 is an apocalyptic number.

21228480 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 21228480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46640496).

21228480 is an abundant number, since it is smaller than the sum of its proper divisors (72052512).

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

21228480 is an equidigital number, since it uses as much as digits as its factorization.

21228480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 21228480 is about 4607.4374656635. The cubic root of 21228480 is about 276.8893805153.

The spelling of 21228480 in words is "twenty-one million, two hundred twenty-eight thousand, four hundred eighty".