21246224 has 10 divisors (see below), whose sum is σ = 41164590. Its totient is φ = 10623104.

The previous prime is 21246221. The next prime is 21246229. The reversal of 21246224 is 42264212.

It can be written as a sum of positive squares in only one way, i.e., 11833600 + 9412624 = 3440^2 + 3068^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21246224.

It is not an unprimeable number, because it can be changed into a prime (21246221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 663929 + ... + 663960.

It is an arithmetic number, because the mean of its divisors is an integer number (4116459).

Almost surely, 2^21246224 is an apocalyptic number.

It is an amenable number.

21246224 is a deficient number, since it is larger than the sum of its proper divisors (19918366).

21246224 is a wasteful number, since it uses less digits than its factorization.

21246224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1327897 (or 1327891 counting only the distinct ones).

The product of its digits is 1536, while the sum is 23.

The square root of 21246224 is about 4609.3626457462. The cubic root of 21246224 is about 276.9665057878.

The spelling of 21246224 in words is "twenty-one million, two hundred forty-six thousand, two hundred twenty-four".