16809979 has 2 divisors, whose sum is σ = 16809980. Its totient is φ = 16809978.

The previous prime is 16809977. The next prime is 16809997. The reversal of 16809979 is 97990861.

Together with next prime (16809997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16809979 - 2¹ = 16809977 is a prime.

Together with 16809977, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (16809971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8404989 + 8404990.

It is an arithmetic number, because the mean of its divisors is an integer number (8404990).

Almost surely, 2^16809979 is an apocalyptic number.

16809979 is a deficient number, since it is larger than the sum of its proper divisors (1).

16809979 is an equidigital number, since it uses as much as digits as its factorization.

16809979 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 16809979 is about 4099.9974390236. The cubic root of 16809979 is about 256.1665328790.

The spelling of 16809979 in words is "sixteen million, eight hundred nine thousand, nine hundred seventy-nine".