21124218 has 16 divisors (see below), whose sum is σ = 42471936. Its totient is φ = 7004160.

The previous prime is 21124199. The next prime is 21124253. The reversal of 21124218 is 81242112.

It is a super-2 number, since 2×21124218² = 892465172223048, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21124194 and 21124203.

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, 8071 + ... + 10362.

It is an arithmetic number, because the mean of its divisors is an integer number (2654496).

Almost surely, 2^21124218 is an apocalyptic number.

21124218 is an abundant number, since it is smaller than the sum of its proper divisors (21347718).

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

21124218 is a wasteful number, since it uses less digits than its factorization.

21124218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18629.

The product of its digits is 256, while the sum is 21.

The square root of 21124218 is about 4596.1090065402. The cubic root of 21124218 is about 276.4353295950.

The spelling of 21124218 in words is "twenty-one million, one hundred twenty-four thousand, two hundred eighteen".