21222418 has 16 divisors (see below), whose sum is σ = 36999360. Its totient is φ = 8940816.

The previous prime is 21222401. The next prime is 21222433. The reversal of 21222418 is 81422212.

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, 12021 + ... + 13672.

It is an arithmetic number, because the mean of its divisors is an integer number (2312460).

Almost surely, 2^21222418 is an apocalyptic number.

21222418 is a deficient number, since it is larger than the sum of its proper divisors (15776942).

21222418 is a wasteful number, since it uses less digits than its factorization.

21222418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25761.

The product of its digits is 512, while the sum is 22.

The square root of 21222418 is about 4606.7795692870. The cubic root of 21222418 is about 276.8630218497.

The spelling of 21222418 in words is "twenty-one million, two hundred twenty-two thousand, four hundred eighteen".