201181591 has 4 divisors (see below), whose sum is σ = 216657112. Its totient is φ = 185706072.

The previous prime is 201181583. The next prime is 201181601. The reversal of 201181591 is 195181102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 201181591 - 2³ = 201181583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201181531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7737741 + ... + 7737766.

It is an arithmetic number, because the mean of its divisors is an integer number (54164278).

Almost surely, 2^201181591 is an apocalyptic number.

201181591 is a deficient number, since it is larger than the sum of its proper divisors (15475521).

201181591 is a wasteful number, since it uses less digits than its factorization.

201181591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15475520.

The product of its (nonzero) digits is 720, while the sum is 28.

The square root of 201181591 is about 14183.8496537435. The cubic root of 201181591 is about 585.9529514114.

The spelling of 201181591 in words is "two hundred one million, one hundred eighty-one thousand, five hundred ninety-one".