20985849 has 24 divisors (see below), whose sum is σ = 31286112. Its totient is φ = 13547520.

The previous prime is 20985847. The next prime is 20985857. The reversal of 20985849 is 94858902.

It is not a de Polignac number, because 20985849 - 2¹ = 20985847 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20985847) 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 23 ways as a sum of consecutive naturals, for example, 81529 + ... + 81785.

It is an arithmetic number, because the mean of its divisors is an integer number (1303588).

Almost surely, 2^20985849 is an apocalyptic number.

It is an amenable number.

20985849 is a deficient number, since it is larger than the sum of its proper divisors (10300263).

20985849 is a wasteful number, since it uses less digits than its factorization.

20985849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 517 (or 514 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The square root of 20985849 is about 4581.0314340768. The cubic root of 20985849 is about 275.8304330210.

The spelling of 20985849 in words is "twenty million, nine hundred eighty-five thousand, eight hundred forty-nine".