21738208 has 12 divisors (see below), whose sum is σ = 42797160. Its totient is φ = 10869088.

The previous prime is 21738191. The next prime is 21738221. The reversal of 21738208 is 80283712.

It is a self number, because there is not a number n which added to its sum of digits gives 21738208.

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, 339628 + ... + 339691.

It is an arithmetic number, because the mean of its divisors is an integer number (3566430).

Almost surely, 2^21738208 is an apocalyptic number.

It is an amenable number.

21738208 is a deficient number, since it is larger than the sum of its proper divisors (21058952).

21738208 is an equidigital number, since it uses as much as digits as its factorization.

21738208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 679329 (or 679321 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 21738208 is about 4662.4251200421. The cubic root of 21738208 is about 279.0880534667.

The spelling of 21738208 in words is "twenty-one million, seven hundred thirty-eight thousand, two hundred eight".