1978843 has 4 divisors (see below), whose sum is σ = 1984320. Its totient is φ = 1973368.

The previous prime is 1978807. The next prime is 1978849. The reversal of 1978843 is 3488791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3488791 = 17 ⋅205223.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978843 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1978796 and 1978805.

It is not an unprimeable number, because it can be changed into a prime (1978849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2155 + ... + 2932.

It is an arithmetic number, because the mean of its divisors is an integer number (496080).

2^1978843 is an apocalyptic number.

1978843 is a deficient number, since it is larger than the sum of its proper divisors (5477).

1978843 is an equidigital number, since it uses as much as digits as its factorization.

1978843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5476.

The product of its digits is 48384, while the sum is 40.

The square root of 1978843 is about 1406.7135458223. The cubic root of 1978843 is about 125.5462599894.

The spelling of 1978843 in words is "one million, nine hundred seventy-eight thousand, eight hundred forty-three".