16691819 has 2 divisors, whose sum is σ = 16691820. Its totient is φ = 16691818.

The previous prime is 16691809. The next prime is 16691833. The reversal of 16691819 is 91819661.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16691819 is a prime.

It is a super-2 number, since 2×16691819² = 557233643057522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16691809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8345909 + 8345910.

It is an arithmetic number, because the mean of its divisors is an integer number (8345910).

Almost surely, 2^16691819 is an apocalyptic number.

16691819 is a deficient number, since it is larger than the sum of its proper divisors (1).

16691819 is an equidigital number, since it uses as much as digits as its factorization.

16691819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 41.

The square root of 16691819 is about 4085.5622624065. The cubic root of 16691819 is about 255.5649093475.

The spelling of 16691819 in words is "sixteen million, six hundred ninety-one thousand, eight hundred nineteen".