21399208 has 16 divisors (see below), whose sum is σ = 41057280. Its totient is φ = 10450608.

The previous prime is 21399193. The next prime is 21399221. The reversal of 21399208 is 80299312.

It is a super-2 number, since 2×21399208² = 915852206054528, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30760 + ... + 31447.

It is an arithmetic number, because the mean of its divisors is an integer number (2566080).

Almost surely, 2^21399208 is an apocalyptic number.

It is an amenable number.

21399208 is a deficient number, since it is larger than the sum of its proper divisors (19658072).

21399208 is a wasteful number, since it uses less digits than its factorization.

21399208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62256 (or 62252 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 21399208 is about 4625.9277988313. The cubic root of 21399208 is about 277.6296848057.

The spelling of 21399208 in words is "twenty-one million, three hundred ninety-nine thousand, two hundred eight".