201585128405 has 18 divisors (see below), whose sum is σ = 243365045346. Its totient is φ = 160298683776.

The previous prime is 201585128399. The next prime is 201585128411. The reversal of 201585128405 is 504821585102.

It is an interprime number because it is at equal distance from previous prime (201585128399) and next prime (201585128411).

It can be written as a sum of positive squares in 3 ways, for example, as 3060523684 + 198524604721 = 55322^2 + 445561^2 .

It is not a de Polignac number, because 201585128405 - 2¹⁸ = 201584866261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 199786541 + ... + 199787549.

It is an arithmetic number, because the mean of its divisors is an integer number (13520280297).

Almost surely, 2^201585128405 is an apocalyptic number.

It is an amenable number.

201585128405 is a deficient number, since it is larger than the sum of its proper divisors (41779916941).

201585128405 is an frugal number, since it uses more digits than its factorization.

201585128405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2421 (or 1213 counting only the distinct ones).

The product of its (nonzero) digits is 128000, while the sum is 41.

The spelling of 201585128405 in words is "two hundred one billion, five hundred eighty-five million, one hundred twenty-eight thousand, four hundred five".