16691819661 has 16 divisors (see below), whose sum is σ = 26976678720. Its totient is φ = 10116254160.

The previous prime is 16691819659. The next prime is 16691819689.

16691819661 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 16691819661 - 2¹ = 16691819659 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16691819598 and 16691819607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16691819611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28100410 + ... + 28101003.

It is an arithmetic number, because the mean of its divisors is an integer number (1686042420).

Almost surely, 2^16691819661 is an apocalyptic number.

16691819661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16691819661 is a deficient number, since it is larger than the sum of its proper divisors (10284859059).

16691819661 is a wasteful number, since it uses less digits than its factorization.

16691819661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56201433 (or 56201427 counting only the distinct ones).

The product of its digits is 839808, while the sum is 54.

The spelling of 16691819661 in words is "sixteen billion, six hundred ninety-one million, eight hundred nineteen thousand, six hundred sixty-one".