201511209985 has 8 divisors (see below), whose sum is σ = 241816334760. Its totient is φ = 161207046144.

The previous prime is 201511209961. The next prime is 201511209989. The reversal of 201511209985 is 589902115102.

It can be written as a sum of positive squares in 4 ways, for example, as 17449617409 + 184061592576 = 132097^2 + 429024^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 201511209985 - 2²⁵ = 201477655553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (201511209989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 355359 + ... + 727531.

It is an arithmetic number, because the mean of its divisors is an integer number (30227041845).

Almost surely, 2^201511209985 is an apocalyptic number.

It is an amenable number.

201511209985 is a deficient number, since it is larger than the sum of its proper divisors (40305124775).

201511209985 is a wasteful number, since it uses less digits than its factorization.

201511209985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480467.

The product of its (nonzero) digits is 64800, while the sum is 43.

The spelling of 201511209985 in words is "two hundred one billion, five hundred eleven million, two hundred nine thousand, nine hundred eighty-five".