21106208 has 12 divisors (see below), whose sum is σ = 41552910. Its totient is φ = 10553088.

The previous prime is 21106201. The next prime is 21106213. The reversal of 21106208 is 80260112.

It can be written as a sum of positive squares in only one way, i.e., 10942864 + 10163344 = 3308^2 + 3188^2 .

It is a super-2 number, since 2×21106208² = 890944032278528, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21106208.

It is not an unprimeable number, because it can be changed into a prime (21106201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 329753 + ... + 329816.

Almost surely, 2^21106208 is an apocalyptic number.

It is an amenable number.

21106208 is a deficient number, since it is larger than the sum of its proper divisors (20446702).

21106208 is an equidigital number, since it uses as much as digits as its factorization.

21106208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 659579 (or 659571 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 21106208 is about 4594.1493227800. The cubic root of 21106208 is about 276.3567465545.

The spelling of 21106208 in words is "twenty-one million, one hundred six thousand, two hundred eight".