21267218 has 16 divisors (see below), whose sum is σ = 37234944. Its totient is φ = 8920320.

The previous prime is 21267161. The next prime is 21267227. The reversal of 21267218 is 81276212.

It is a super-2 number, since 2×21267218² = 904589122919048, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15503 + ... + 16818.

It is an arithmetic number, because the mean of its divisors is an integer number (2327184).

Almost surely, 2^21267218 is an apocalyptic number.

21267218 is a deficient number, since it is larger than the sum of its proper divisors (15967726).

21267218 is a wasteful number, since it uses less digits than its factorization.

21267218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32377.

The product of its digits is 2688, while the sum is 29.

The square root of 21267218 is about 4611.6394048104. The cubic root of 21267218 is about 277.0577019249.

The spelling of 21267218 in words is "twenty-one million, two hundred sixty-seven thousand, two hundred eighteen".