21708147 has 8 divisors (see below), whose sum is σ = 29650320. Its totient is φ = 14119040.

The previous prime is 21708139. The next prime is 21708151. The reversal of 21708147 is 74180712.

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 21708147 - 2³ = 21708139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21708107) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88122 + ... + 88367.

It is an arithmetic number, because the mean of its divisors is an integer number (3706290).

Almost surely, 2^21708147 is an apocalyptic number.

21708147 is a deficient number, since it is larger than the sum of its proper divisors (7942173).

21708147 is a wasteful number, since it uses less digits than its factorization.

21708147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176533.

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 21708147 is about 4659.2002532624. The cubic root of 21708147 is about 278.9593471170.

Adding to 21708147 its reverse (74180712), we get a palindrome (95888859).

The spelling of 21708147 in words is "twenty-one million, seven hundred eight thousand, one hundred forty-seven".