20101985 has 16 divisors (see below), whose sum is σ = 24624000. Its totient is φ = 15751296.

The previous prime is 20101979. The next prime is 20101993. The reversal of 20101985 is 58910102.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20101985 is a prime.

It is a Curzon number.

It is an unprimeable number.

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, 88442 + ... + 88668.

It is an arithmetic number, because the mean of its divisors is an integer number (1539000).

Almost surely, 2^20101985 is an apocalyptic number.

It is an amenable number.

20101985 is a deficient number, since it is larger than the sum of its proper divisors (4522015).

20101985 is a wasteful number, since it uses less digits than its factorization.

20101985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520.

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

The square root of 20101985 is about 4483.5237258210. The cubic root of 20101985 is about 271.9023627720.

The spelling of 20101985 in words is "twenty million, one hundred one thousand, nine hundred eighty-five".