1966809 has 32 divisors (see below), whose sum is σ = 3064320. Its totient is φ = 1112832.

The previous prime is 1966807. The next prime is 1966813. The reversal of 1966809 is 9086691.

It is not a de Polignac number, because 1966809 - 2¹ = 1966807 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (1966807) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41824 + ... + 41870.

It is an arithmetic number, because the mean of its divisors is an integer number (95760).

2^1966809 is an apocalyptic number.

It is an amenable number.

1966809 is a deficient number, since it is larger than the sum of its proper divisors (1097511).

1966809 is a wasteful number, since it uses less digits than its factorization.

1966809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129.

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 1966809 is about 1402.4296773814. The cubic root of 1966809 is about 125.2912462115.

It can be divided in two parts, 1966 and 809, that added together give a triangular number (2775 = T₇₄).

The spelling of 1966809 in words is "one million, nine hundred sixty-six thousand, eight hundred nine".