201387991 has 8 divisors (see below), whose sum is σ = 234855200. Its totient is φ = 172617984.

The previous prime is 201387961. The next prime is 201388037. The reversal of 201387991 is 199783102.

It is not a de Polignac number, because 201387991 - 2¹⁹ = 200863703 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 (201387961) 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, 293226 + ... + 293911.

It is an arithmetic number, because the mean of its divisors is an integer number (29356900).

Almost surely, 2^201387991 is an apocalyptic number.

201387991 is a deficient number, since it is larger than the sum of its proper divisors (33467209).

201387991 is an frugal number, since it uses more digits than its factorization.

201387991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 587158 (or 587144 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 201387991 is about 14191.1236693928. The cubic root of 201387991 is about 586.1532668791.

The spelling of 201387991 in words is "two hundred one million, three hundred eighty-seven thousand, nine hundred ninety-one".