21298224 has 40 divisors (see below), whose sum is σ = 55187440. Its totient is φ = 7077888.

The previous prime is 21298217. The next prime is 21298241. The reversal of 21298224 is 42289212.

It is a Cunningham number, because it is equal to 4615²-1.

It is a super-2 number, since 2×21298224² = 907228691108352, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21298191 and 21298200.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27312 + ... + 28080.

It is an arithmetic number, because the mean of its divisors is an integer number (1379686).

Almost surely, 2^21298224 is an apocalyptic number.

21298224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21298224 is an abundant number, since it is smaller than the sum of its proper divisors (33889216).

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

21298224 is a wasteful number, since it uses less digits than its factorization.

21298224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1357 (or 1351 counting only the distinct ones).

The product of its digits is 4608, while the sum is 30.

The square root of 21298224 is about 4614.9998916576. Note that the first 3 decimals coincide. The cubic root of 21298224 is about 277.1922796231.

The spelling of 21298224 in words is "twenty-one million, two hundred ninety-eight thousand, two hundred twenty-four".