191998565 has 12 divisors (see below), whose sum is σ = 253248492. Its totient is φ = 139634880.

The previous prime is 191998529. The next prime is 191998571. The reversal of 191998565 is 565899191.

It can be written as a sum of positive squares in 2 ways, for example, as 35022724 + 156975841 = 5918^2 + 12529^2 .

It is not a de Polignac number, because 191998565 - 2⁸ = 191998309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 158072 + ... + 159281.

It is an arithmetic number, because the mean of its divisors is an integer number (21104041).

Almost surely, 2^191998565 is an apocalyptic number.

It is an amenable number.

191998565 is a deficient number, since it is larger than the sum of its proper divisors (61249927).

191998565 is a wasteful number, since it uses less digits than its factorization.

191998565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317380 (or 317369 counting only the distinct ones).

The product of its digits is 874800, while the sum is 53.

The square root of 191998565 is about 13856.3546793520. The cubic root of 191998565 is about 576.8983908776.

The spelling of 191998565 in words is "one hundred ninety-one million, nine hundred ninety-eight thousand, five hundred sixty-five".