201991387 has 8 divisors (see below), whose sum is σ = 220283840. Its totient is φ = 184092480.

The previous prime is 201991369. The next prime is 201991411. The reversal of 201991387 is 783199102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 201991387 - 2⁷ = 201991259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201991357) 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, 97314 + ... + 99367.

It is an arithmetic number, because the mean of its divisors is an integer number (27535480).

Almost surely, 2^201991387 is an apocalyptic number.

201991387 is a deficient number, since it is larger than the sum of its proper divisors (18292453).

201991387 is a wasteful number, since it uses less digits than its factorization.

201991387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196773.

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

The square root of 201991387 is about 14212.3673960393. The cubic root of 201991387 is about 586.7380913742.

The spelling of 201991387 in words is "two hundred one million, nine hundred ninety-one thousand, three hundred eighty-seven".