1980778 has 4 divisors (see below), whose sum is σ = 2971170. Its totient is φ = 990388.

The previous prime is 1980773. The next prime is 1980791. The reversal of 1980778 is 8770891.

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

It can be written as a sum of positive squares in only one way, i.e., 1270129 + 710649 = 1127^2 + 843^2 .

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 1980778.

It is not an unprimeable number, because it can be changed into a prime (1980773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495193 + ... + 495196.

2^1980778 is an apocalyptic number.

1980778 is a deficient number, since it is larger than the sum of its proper divisors (990392).

1980778 is an equidigital number, since it uses as much as digits as its factorization.

1980778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 990391.

The product of its (nonzero) digits is 28224, while the sum is 40.

The square root of 1980778 is about 1407.4011510582. The cubic root of 1980778 is about 125.5871682159.

Adding to 1980778 its product of nonzero digits (28224), we get a palindrome (2009002).

The spelling of 1980778 in words is "one million, nine hundred eighty thousand, seven hundred seventy-eight".