21224018 has 8 divisors (see below), whose sum is σ = 31869948. Its totient is φ = 10600704.

The previous prime is 21224003. The next prime is 21224023. The reversal of 21224018 is 81042212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20729809 + 494209 = 4553^2 + 703^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon 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, 3071 + ... + 7202.

Almost surely, 2^21224018 is an apocalyptic number.

21224018 is a deficient number, since it is larger than the sum of its proper divisors (10645930).

21224018 is a wasteful number, since it uses less digits than its factorization.

21224018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11308.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21224018 is about 4606.9532231183. The cubic root of 21224018 is about 276.8699794248.

The spelling of 21224018 in words is "twenty-one million, two hundred twenty-four thousand, eighteen".