21608747 has 8 divisors (see below), whose sum is σ = 22254144. Its totient is φ = 20969928.

The previous prime is 21608711. The next prime is 21608749. The reversal of 21608747 is 74780612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21608747 - 2¹⁶ = 21543211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21608749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5468 + ... + 8550.

It is an arithmetic number, because the mean of its divisors is an integer number (2781768).

Almost surely, 2^21608747 is an apocalyptic number.

21608747 is a deficient number, since it is larger than the sum of its proper divisors (645397).

21608747 is a wasteful number, since it uses less digits than its factorization.

21608747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3289.

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 21608747 is about 4648.5209475703. The cubic root of 21608747 is about 278.5329175153.

The spelling of 21608747 in words is "twenty-one million, six hundred eight thousand, seven hundred forty-seven".