201991143 has 4 divisors (see below), whose sum is σ = 269321528. Its totient is φ = 134660760.

The previous prime is 201991123. The next prime is 201991159. The reversal of 201991143 is 341199102.

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

It is not a de Polignac number, because 201991143 - 2¹⁰ = 201990119 is a prime.

It is a super-3 number, since 3×201991143³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 201991143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201991123) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 33665188 + ... + 33665193.

It is an arithmetic number, because the mean of its divisors is an integer number (67330382).

Almost surely, 2^201991143 is an apocalyptic number.

201991143 is a deficient number, since it is larger than the sum of its proper divisors (67330385).

201991143 is an equidigital number, since it uses as much as digits as its factorization.

201991143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67330384.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 201991143 is about 14212.3588119636. The cubic root of 201991143 is about 586.7378551197.

The spelling of 201991143 in words is "two hundred one million, nine hundred ninety-one thousand, one hundred forty-three".