191716856321 has 16 divisors (see below), whose sum is σ = 202716945600. Its totient is φ = 180809558208.

The previous prime is 191716856311. The next prime is 191716856327. The reversal of 191716856321 is 123658617191.

It is a cyclic number.

It is not a de Polignac number, because 191716856321 - 2²² = 191712662017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 191716856321.

It is not an unprimeable number, because it can be changed into a prime (191716856327) 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, 3840695 + ... + 3890291.

It is an arithmetic number, because the mean of its divisors is an integer number (12669809100).

Almost surely, 2^191716856321 is an apocalyptic number.

It is an amenable number.

191716856321 is a deficient number, since it is larger than the sum of its proper divisors (11000089279).

191716856321 is a wasteful number, since it uses less digits than its factorization.

191716856321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50528.

The product of its digits is 544320, while the sum is 50.

The spelling of 191716856321 in words is "one hundred ninety-one billion, seven hundred sixteen million, eight hundred fifty-six thousand, three hundred twenty-one".