1985778 has 12 divisors (see below), whose sum is σ = 4302558. Its totient is φ = 661920.

The previous prime is 1985771. The next prime is 1985779. The reversal of 1985778 is 8775891.

It can be written as a sum of positive squares in only one way, i.e., 1505529 + 480249 = 1227^2 + 693^2 .

It is not an unprimeable number, because it can be changed into a prime (1985771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 55143 + ... + 55178.

2^1985778 is an apocalyptic number.

1985778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1985778 is an abundant number, since it is smaller than the sum of its proper divisors (2316780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1985778 is a wasteful number, since it uses less digits than its factorization.

1985778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110329 (or 110326 counting only the distinct ones).

The product of its digits is 141120, while the sum is 45.

The square root of 1985778 is about 1409.1763551806. The cubic root of 1985778 is about 125.6927510093.

The spelling of 1985778 in words is "one million, nine hundred eighty-five thousand, seven hundred seventy-eight".