16856183891 has 4 divisors (see below), whose sum is σ = 16866635712. Its totient is φ = 16845732072.

The previous prime is 16856183881. The next prime is 16856183923. The reversal of 16856183891 is 19838165861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19838165861 = 17 ⋅1166950933.

It is a cyclic number.

It is not a de Polignac number, because 16856183891 - 2¹⁰ = 16856182867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16856183881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5223491 + ... + 5226716.

It is an arithmetic number, because the mean of its divisors is an integer number (4216658928).

Almost surely, 2^16856183891 is an apocalyptic number.

16856183891 is a deficient number, since it is larger than the sum of its proper divisors (10451821).

16856183891 is a wasteful number, since it uses less digits than its factorization.

16856183891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10451820.

The product of its digits is 2488320, while the sum is 56.

The spelling of 16856183891 in words is "sixteen billion, eight hundred fifty-six million, one hundred eighty-three thousand, eight hundred ninety-one".