16806409 has 4 divisors (see below), whose sum is σ = 16825104. Its totient is φ = 16787716.

The previous prime is 16806403. The next prime is 16806443. The reversal of 16806409 is 90460861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16806409 - 2¹³ = 16798217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16806403) 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, 7927 + ... + 9820.

It is an arithmetic number, because the mean of its divisors is an integer number (4206276).

Almost surely, 2^16806409 is an apocalyptic number.

It is an amenable number.

16806409 is a deficient number, since it is larger than the sum of its proper divisors (18695).

16806409 is an equidigital number, since it uses as much as digits as its factorization.

16806409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18694.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 16806409 is about 4099.5620497804. The cubic root of 16806409 is about 256.1483972373.

It can be divided in two parts, 1680 and 6409, that multiplied together give a triangular number (10767120 = T₄₆₄₀).

The spelling of 16806409 in words is "sixteen million, eight hundred six thousand, four hundred nine".