191798689257 has 24 divisors (see below), whose sum is σ = 316645602624. Its totient is φ = 109590408864.

The previous prime is 191798689249. The next prime is 191798689261. The reversal of 191798689257 is 752986897191.

It is a happy number.

It is not a de Polignac number, because 191798689257 - 2³ = 191798689249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (191798689267) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 708598 + ... + 941120.

It is an arithmetic number, because the mean of its divisors is an integer number (13193566776).

Almost surely, 2^191798689257 is an apocalyptic number.

It is an amenable number.

191798689257 is a deficient number, since it is larger than the sum of its proper divisors (124846913367).

191798689257 is a wasteful number, since it uses less digits than its factorization.

191798689257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245629 (or 245626 counting only the distinct ones).

The product of its digits is 137168640, while the sum is 72.

The spelling of 191798689257 in words is "one hundred ninety-one billion, seven hundred ninety-eight million, six hundred eighty-nine thousand, two hundred fifty-seven".