21224508 has 12 divisors (see below), whose sum is σ = 49523880. Its totient is φ = 7074832.

The previous prime is 21224503. The next prime is 21224509. The reversal of 21224508 is 80542212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 884343 + ... + 884366.

It is an arithmetic number, because the mean of its divisors is an integer number (4126990).

Almost surely, 2^21224508 is an apocalyptic number.

It is an amenable number.

21224508 is an abundant number, since it is smaller than the sum of its proper divisors (28299372).

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

21224508 is a wasteful number, since it uses less digits than its factorization.

21224508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1768716 (or 1768714 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21224508 is about 4607.0064032949. The cubic root of 21224508 is about 276.8721101122.

The spelling of 21224508 in words is "twenty-one million, two hundred twenty-four thousand, five hundred eight".