21568338 has 48 divisors (see below), whose sum is σ = 51551136. Its totient is φ = 6462720.

The previous prime is 21568333. The next prime is 21568357. The reversal of 21568338 is 83386512.

It is not an unprimeable number, because it can be changed into a prime (21568331) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 18645 + ... + 19767.

It is an arithmetic number, because the mean of its divisors is an integer number (1073982).

Almost surely, 2^21568338 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21568338, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25775568).

21568338 is an abundant number, since it is smaller than the sum of its proper divisors (29982798).

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

21568338 is a wasteful number, since it uses less digits than its factorization.

21568338 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1239 (or 1236 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21568338 is about 4644.1724774173. The cubic root of 21568338 is about 278.3591875617.

The spelling of 21568338 in words is "twenty-one million, five hundred sixty-eight thousand, three hundred thirty-eight".