21286218 has 16 divisors (see below), whose sum is σ = 42650496. Its totient is φ = 7082400.

The previous prime is 21286189. The next prime is 21286229. The reversal of 21286218 is 81268212.

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, 655 + ... + 6557.

It is an arithmetic number, because the mean of its divisors is an integer number (2665656).

Almost surely, 2^21286218 is an apocalyptic number.

21286218 is an abundant number, since it is smaller than the sum of its proper divisors (21364278).

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

21286218 is a wasteful number, since it uses less digits than its factorization.

21286218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6509.

The product of its digits is 3072, while the sum is 30.

The square root of 21286218 is about 4613.6989498666. The cubic root of 21286218 is about 277.1401845746.

The spelling of 21286218 in words is "twenty-one million, two hundred eighty-six thousand, two hundred eighteen".