201551985 has 24 divisors (see below), whose sum is σ = 349689600. Its totient is φ = 107392032.

The previous prime is 201551963. The next prime is 201552011. The reversal of 201551985 is 589155102.

It is a happy number.

201551985 is a `hidden beast` number, since 20 + 1 + 551 + 9 + 85 = 666.

It is not a de Polignac number, because 201551985 - 2⁵ = 201551953 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 (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 82816 + ... + 85214.

It is an arithmetic number, because the mean of its divisors is an integer number (14570400).

Almost surely, 2^201551985 is an apocalyptic number.

It is an amenable number.

201551985 is a deficient number, since it is larger than the sum of its proper divisors (148137615).

201551985 is a wasteful number, since it uses less digits than its factorization.

201551985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4277 (or 4274 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 36.

The square root of 201551985 is about 14196.9005420197. The cubic root of 201551985 is about 586.3123288932.

The spelling of 201551985 in words is "two hundred one million, five hundred fifty-one thousand, nine hundred eighty-five".