21220448 has 24 divisors (see below), whose sum is σ = 42252840. Its totient is φ = 10489600.

The previous prime is 21220429. The next prime is 21220477. The reversal of 21220448 is 84402212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 878 + ... + 6573.

It is an arithmetic number, because the mean of its divisors is an integer number (1760535).

Almost surely, 2^21220448 is an apocalyptic number.

It is an amenable number.

21220448 is a deficient number, since it is larger than the sum of its proper divisors (21032392).

21220448 is an equidigital number, since it uses as much as digits as its factorization.

21220448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7550 (or 7542 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 23.

The square root of 21220448 is about 4606.5657490152. The cubic root of 21220448 is about 276.8544548549.

The spelling of 21220448 in words is "twenty-one million, two hundred twenty thousand, four hundred forty-eight".