16809997 has 2 divisors, whose sum is σ = 16809998. Its totient is φ = 16809996.

The previous prime is 16809979. The next prime is 16810007. The reversal of 16809997 is 79990861.

Together with previous prime (16809979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16597476 + 212521 = 4074^2 + 461^2 .

It is an emirp because it is prime and its reverse (79990861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16809997 - 2⁷ = 16809869 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16809997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16809977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8404998 + 8404999.

It is an arithmetic number, because the mean of its divisors is an integer number (8404999).

Almost surely, 2^16809997 is an apocalyptic number.

It is an amenable number.

16809997 is a deficient number, since it is larger than the sum of its proper divisors (1).

16809997 is an equidigital number, since it uses as much as digits as its factorization.

16809997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 244944, while the sum is 49.

The square root of 16809997 is about 4099.9996341463. Note that the first 3 decimals coincide. The cubic root of 16809997 is about 256.1666243128.

The spelling of 16809997 in words is "sixteen million, eight hundred nine thousand, nine hundred ninety-seven".