20985605 has 8 divisors (see below), whose sum is σ = 25995264. Its totient is φ = 16246800.

The previous prime is 20985593. The next prime is 20985617. The reversal of 20985605 is 50658902.

It is an interprime number because it is at equal distance from previous prime (20985593) and next prime (20985617).

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

It is not a de Polignac number, because 20985605 - 2¹⁰ = 20984581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67541 + ... + 67850.

It is an arithmetic number, because the mean of its divisors is an integer number (3249408).

Almost surely, 2^20985605 is an apocalyptic number.

It is an amenable number.

20985605 is a deficient number, since it is larger than the sum of its proper divisors (5009659).

20985605 is a wasteful number, since it uses less digits than its factorization.

20985605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135427.

The product of its (nonzero) digits is 21600, while the sum is 35.

The square root of 20985605 is about 4581.0048024424. The cubic root of 20985605 is about 275.8293640009.

The spelling of 20985605 in words is "twenty million, nine hundred eighty-five thousand, six hundred five".