21606017 has 8 divisors (see below), whose sum is σ = 22058112. Its totient is φ = 21157200.

The previous prime is 21606007. The next prime is 21606019. The reversal of 21606017 is 71060612.

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 21606017 - 2¹⁰ = 21604993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21605983 and 21606001.

It is not an unprimeable number, because it can be changed into a prime (21606019) 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 7 ways as a sum of consecutive naturals, for example, 15878 + ... + 17184.

It is an arithmetic number, because the mean of its divisors is an integer number (2757264).

Almost surely, 2^21606017 is an apocalyptic number.

It is an amenable number.

21606017 is a deficient number, since it is larger than the sum of its proper divisors (452095).

21606017 is a wasteful number, since it uses less digits than its factorization.

21606017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1639.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 21606017 is about 4648.2272965078. The cubic root of 21606017 is about 278.5211872826.

Adding to 21606017 its reverse (71060612), we get a palindrome (92666629).

The spelling of 21606017 in words is "twenty-one million, six hundred six thousand, seventeen".