21227776 has 36 divisors (see below), whose sum is σ = 42844284. Its totient is φ = 10496000.

The previous prime is 21227753. The next prime is 21227779. The reversal of 21227776 is 67772212.

It can be written as a sum of positive squares in 2 ways, for example, as 14258176 + 6969600 = 3776^2 + 2640^2 .

It is not an unprimeable number, because it can be changed into a prime (21227779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25446 + ... + 26266.

It is an arithmetic number, because the mean of its divisors is an integer number (1190119).

Almost surely, 2^21227776 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 21227776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21422142).

21227776 is an abundant number, since it is smaller than the sum of its proper divisors (21616508).

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

21227776 is an equidigital number, since it uses as much as digits as its factorization.

21227776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 938 (or 924 counting only the distinct ones).

The product of its digits is 16464, while the sum is 34.

The square root of 21227776 is about 4607.3610668147. The cubic root of 21227776 is about 276.8863196543.

Adding to 21227776 its reverse (67772212), we get a palindrome (88999988).

The spelling of 21227776 in words is "twenty-one million, two hundred twenty-seven thousand, seven hundred seventy-six".