191988565 has 16 divisors (see below), whose sum is σ = 247034880. Its totient is φ = 142721280.

The previous prime is 191988547. The next prime is 191988569. The reversal of 191988565 is 565889191.

191988565 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 191988565 - 2¹¹ = 191986517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191988569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7581 + ... + 21010.

It is an arithmetic number, because the mean of its divisors is an integer number (15439680).

Almost surely, 2^191988565 is an apocalyptic number.

It is an amenable number.

191988565 is a deficient number, since it is larger than the sum of its proper divisors (55046315).

191988565 is a wasteful number, since it uses less digits than its factorization.

191988565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28692.

The product of its digits is 777600, while the sum is 52.

The square root of 191988565 is about 13855.9938293866. The cubic root of 191988565 is about 576.8883750318. Note that the first 3 decimals are identical.

The spelling of 191988565 in words is "one hundred ninety-one million, nine hundred eighty-eight thousand, five hundred sixty-five".