191798865 has 12 divisors (see below), whose sum is σ = 332451444. Its totient is φ = 102292704.

The previous prime is 191798857. The next prime is 191798917. The reversal of 191798865 is 568897191.

It can be written as a sum of positive squares in 2 ways, for example, as 106254864 + 85544001 = 10308^2 + 9249^2 .

It is not a de Polignac number, because 191798865 - 2³ = 191798857 is a prime.

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, 2131054 + ... + 2131143.

It is an arithmetic number, because the mean of its divisors is an integer number (27704287).

Almost surely, 2^191798865 is an apocalyptic number.

191798865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

191798865 is a deficient number, since it is larger than the sum of its proper divisors (140652579).

191798865 is a wasteful number, since it uses less digits than its factorization.

191798865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4262208 (or 4262205 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 54.

The square root of 191798865 is about 13849.1467246181. The cubic root of 191798865 is about 576.6983085240.

The spelling of 191798865 in words is "one hundred ninety-one million, seven hundred ninety-eight thousand, eight hundred sixty-five".