21258208 has 12 divisors (see below), whose sum is σ = 41852160. Its totient is φ = 10629088.

The previous prime is 21258199. The next prime is 21258253. The reversal of 21258208 is 80285212.

It is a super-2 number, since 2×21258208² = 903822814742528, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332128 + ... + 332191.

It is an arithmetic number, because the mean of its divisors is an integer number (3487680).

Almost surely, 2^21258208 is an apocalyptic number.

It is an amenable number.

21258208 is a deficient number, since it is larger than the sum of its proper divisors (20593952).

21258208 is an equidigital number, since it uses as much as digits as its factorization.

21258208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664329 (or 664321 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 21258208 is about 4610.6624252921. The cubic root of 21258208 is about 277.0185706118.

The spelling of 21258208 in words is "twenty-one million, two hundred fifty-eight thousand, two hundred eight".