20011985 has 16 divisors (see below), whose sum is σ = 28085376. Its totient is φ = 13402368.

The previous prime is 20011967. The next prime is 20011987. The reversal of 20011985 is 58911002.

It is a happy number.

It is not a de Polignac number, because 20011985 - 2¹⁰ = 20010961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20011987) 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 15 ways as a sum of consecutive naturals, for example, 5144 + ... + 8153.

It is an arithmetic number, because the mean of its divisors is an integer number (1755336).

Almost surely, 2^20011985 is an apocalyptic number.

It is an amenable number.

20011985 is a deficient number, since it is larger than the sum of its proper divisors (8073391).

20011985 is a wasteful number, since it uses less digits than its factorization.

20011985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13352.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 20011985 is about 4473.4757180519. The cubic root of 20011985 is about 271.4959713244.

Adding to 20011985 its reverse (58911002), we get a palindrome (78922987).

The spelling of 20011985 in words is "twenty million, eleven thousand, nine hundred eighty-five".