21026218 has 8 divisors (see below), whose sum is σ = 32626980. Its totient is φ = 10150560.

The previous prime is 21026197. The next prime is 21026231. The reversal of 21026218 is 81262012.

It can be written as a sum of positive squares in 2 ways, for example, as 18601969 + 2424249 = 4313^2 + 1557^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 181203 + ... + 181318.

Almost surely, 2^21026218 is an apocalyptic number.

21026218 is a deficient number, since it is larger than the sum of its proper divisors (11600762).

21026218 is a wasteful number, since it uses less digits than its factorization.

21026218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362552.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21026218 is about 4585.4354209824. The cubic root of 21026218 is about 276.0071849281.

The spelling of 21026218 in words is "twenty-one million, twenty-six thousand, two hundred eighteen".