201991855 has 16 divisors (see below), whose sum is σ = 267109920. Its totient is φ = 145692288.

The previous prime is 201991847. The next prime is 201991879. The reversal of 201991855 is 558199102.

It is a cyclic number.

It is not a de Polignac number, because 201991855 - 2³ = 201991847 is a prime.

It is a congruent 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, 33340 + ... + 38929.

It is an arithmetic number, because the mean of its divisors is an integer number (16694370).

Almost surely, 2^201991855 is an apocalyptic number.

201991855 is a deficient number, since it is larger than the sum of its proper divisors (65118065).

201991855 is a wasteful number, since it uses less digits than its factorization.

201991855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72330.

The product of its (nonzero) digits is 32400, while the sum is 40.

The square root of 201991855 is about 14212.3838605633. The cubic root of 201991855 is about 586.7385445177.

The spelling of 201991855 in words is "two hundred one million, nine hundred ninety-one thousand, eight hundred fifty-five".