20985685 has 8 divisors (see below), whose sum is σ = 28780416. Its totient is φ = 14390160.

The previous prime is 20985649. The next prime is 20985703. The reversal of 20985685 is 58658902.

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

It is not a de Polignac number, because 20985685 - 2¹¹ = 20983637 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 299761 + ... + 299830.

It is an arithmetic number, because the mean of its divisors is an integer number (3597552).

Almost surely, 2^20985685 is an apocalyptic number.

It is an amenable number.

20985685 is a deficient number, since it is larger than the sum of its proper divisors (7794731).

20985685 is an equidigital number, since it uses as much as digits as its factorization.

20985685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599603.

The product of its (nonzero) digits is 172800, while the sum is 43.

The square root of 20985685 is about 4581.0135341429. The cubic root of 20985685 is about 275.8297145002.

The spelling of 20985685 in words is "twenty million, nine hundred eighty-five thousand, six hundred eighty-five".