1990678 has 4 divisors (see below), whose sum is σ = 2986020. Its totient is φ = 995338.

The previous prime is 1990661. The next prime is 1990679. The reversal of 1990678 is 8760991.

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

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 self number, because there is not a number n which added to its sum of digits gives 1990678.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 497668 + ... + 497671.

It is an arithmetic number, because the mean of its divisors is an integer number (746505).

2^1990678 is an apocalyptic number.

1990678 is a deficient number, since it is larger than the sum of its proper divisors (995342).

1990678 is an equidigital number, since it uses as much as digits as its factorization.

1990678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995341.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 1990678 is about 1410.9138882299. The cubic root of 1990678 is about 125.7960503359.

The spelling of 1990678 in words is "one million, nine hundred ninety thousand, six hundred seventy-eight".