16779985 has 4 divisors (see below), whose sum is σ = 20135988. Its totient is φ = 13423984.

The previous prime is 16779979. The next prime is 16779989. The reversal of 16779985 is 58997761.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58997761 = 7681².

It can be written as a sum of positive squares in 2 ways, for example, as 4227136 + 12552849 = 2056^2 + 3543^2 .

It is a cyclic number.

It is not a de Polignac number, because 16779985 - 2⁵ = 16779953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16779989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1677994 + ... + 1678003.

It is an arithmetic number, because the mean of its divisors is an integer number (5033997).

Almost surely, 2^16779985 is an apocalyptic number.

It is an amenable number.

16779985 is a deficient number, since it is larger than the sum of its proper divisors (3356003).

16779985 is an equidigital number, since it uses as much as digits as its factorization.

16779985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3356002.

The product of its digits is 952560, while the sum is 52.

The square root of 16779985 is about 4096.3379987496. The cubic root of 16779985 is about 256.0140830876.

The spelling of 16779985 in words is "sixteen million, seven hundred seventy-nine thousand, nine hundred eighty-five".