21711208 has 16 divisors (see below), whose sum is σ = 40881060. Its totient is φ = 10809600.

The previous prime is 21711163. The next prime is 21711229. The reversal of 21711208 is 80211712.

It can be written as a sum of positive squares in 2 ways, for example, as 17123044 + 4588164 = 4138^2 + 2142^2 .

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, 3703 + ... + 7558.

Almost surely, 2^21711208 is an apocalyptic number.

It is an amenable number.

21711208 is a deficient number, since it is larger than the sum of its proper divisors (19169852).

21711208 is a wasteful number, since it uses less digits than its factorization.

21711208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11508 (or 11504 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 21711208 is about 4659.5287315350. The cubic root of 21711208 is about 278.9724582380.

The spelling of 21711208 in words is "twenty-one million, seven hundred eleven thousand, two hundred eight".