1778816 has 32 divisors (see below), whose sum is σ = 3819900. Its totient is φ = 820224.

The previous prime is 1778813. The next prime is 1778851. The reversal of 1778816 is 6188771.

It can be written as a sum of positive squares in 2 ways, for example, as 1700416 + 78400 = 1304^2 + 280^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a nialpdrome in base 8.

It is a zygodrome in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 1778816.

It is not an unprimeable number, because it can be changed into a prime (1778813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1130 + ... + 2198.

2^1778816 is an apocalyptic number.

1778816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1778816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1909950).

1778816 is an abundant number, since it is smaller than the sum of its proper divisors (2041084).

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

1778816 is a wasteful number, since it uses less digits than its factorization.

1778816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1096 (or 1084 counting only the distinct ones).

The product of its digits is 18816, while the sum is 38.

The square root of 1778816 is about 1333.7226098406. The cubic root of 1778816 is about 121.1649504535.

The spelling of 1778816 in words is "one million, seven hundred seventy-eight thousand, eight hundred sixteen".