21398208 has 56 divisors (see below), whose sum is σ = 60978288. Its totient is φ = 6583296.

The previous prime is 21398191. The next prime is 21398227. The reversal of 21398208 is 80289312.

It is a super-2 number, since 2×21398208² = 915766611222528, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1791 + ... + 6782.

It is an arithmetic number, because the mean of its divisors is an integer number (1088898).

Almost surely, 2^21398208 is an apocalyptic number.

It is an amenable number.

21398208 is an abundant number, since it is smaller than the sum of its proper divisors (39580080).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21398208 is a wasteful number, since it uses less digits than its factorization.

21398208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8601 (or 8591 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 21398208 is about 4625.8197111431. The cubic root of 21398208 is about 277.6253601284.

The spelling of 21398208 in words is "twenty-one million, three hundred ninety-eight thousand, two hundred eight".