21122218 has 8 divisors (see below), whose sum is σ = 34120548. Its totient is φ = 9748704.

The previous prime is 21122203. The next prime is 21122221. The reversal of 21122218 is 81222112.

It can be written as a sum of positive squares in 2 ways, for example, as 21095649 + 26569 = 4593^2 + 163^2 .

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

It is a super-2 number, since 2×21122218² = 892296186479048, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21122195 and 21122204.

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, 406171 + ... + 406222.

Almost surely, 2^21122218 is an apocalyptic number.

21122218 is a deficient number, since it is larger than the sum of its proper divisors (12998330).

21122218 is a wasteful number, since it uses less digits than its factorization.

21122218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812408.

The product of its digits is 128, while the sum is 19.

The square root of 21122218 is about 4595.8914260457. The cubic root of 21122218 is about 276.4266051993.

The spelling of 21122218 in words is "twenty-one million, one hundred twenty-two thousand, two hundred eighteen".