21056206 has 12 divisors (see below), whose sum is σ = 32378616. Its totient is φ = 10269680.

The previous prime is 21056179. The next prime is 21056227. The reversal of 21056206 is 60265012.

It is a super-2 number, since 2×21056206² = 886727622228872, which contains 22 as substring.

It is a congruent number.

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 5 ways as a sum of consecutive naturals, for example, 231 + ... + 6493.

It is an arithmetic number, because the mean of its divisors is an integer number (2698218).

Almost surely, 2^21056206 is an apocalyptic number.

21056206 is a deficient number, since it is larger than the sum of its proper divisors (11322410).

21056206 is an equidigital number, since it uses as much as digits as its factorization.

21056206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6347 (or 6306 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21056206 is about 4588.7041743830. The cubic root of 21056206 is about 276.1383381972.

The spelling of 21056206 in words is "twenty-one million, fifty-six thousand, two hundred six".