1966643 has 4 divisors (see below), whose sum is σ = 2247600. Its totient is φ = 1685688.

The previous prime is 1966619. The next prime is 1966663. The reversal of 1966643 is 3466691.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1966643 - 2⁸ = 1966387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1966603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140468 + ... + 140481.

It is an arithmetic number, because the mean of its divisors is an integer number (561900).

2^1966643 is an apocalyptic number.

1966643 is a deficient number, since it is larger than the sum of its proper divisors (280957).

1966643 is an equidigital number, since it uses as much as digits as its factorization.

1966643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280956.

The product of its digits is 23328, while the sum is 35.

The square root of 1966643 is about 1402.3704931294. The cubic root of 1966643 is about 125.2877212238.

The spelling of 1966643 in words is "one million, nine hundred sixty-six thousand, six hundred forty-three".