21227520 has 96 divisors (see below), whose sum is σ = 68009760. Its totient is φ = 5652480.

The previous prime is 21227513. The next prime is 21227527. The reversal of 21227520 is 2572212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21227513) and next prime (21227527).

It is a tau number, because it is divible by the number of its divisors (96).

It is a zygodrome in base 4.

It is not an unprimeable number, because it can be changed into a prime (21227527) 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, 30375 + ... + 31065.

It is an arithmetic number, because the mean of its divisors is an integer number (708435).

Almost surely, 2^21227520 is an apocalyptic number.

21227520 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 21227520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34004880).

21227520 is an abundant number, since it is smaller than the sum of its proper divisors (46782240).

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

21227520 is an equidigital number, since it uses as much as digits as its factorization.

21227520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 721 (or 701 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21227520 is about 4607.3332851010. Note that the first 3 decimals coincide. The cubic root of 21227520 is about 276.8852065972.

Adding to 21227520 its reverse (2572212), we get a palindrome (23799732).

The spelling of 21227520 in words is "twenty-one million, two hundred twenty-seven thousand, five hundred twenty".