1778728 has 32 divisors (see below), whose sum is σ = 3980160. Its totient is φ = 728640.

The previous prime is 1778719. The next prime is 1778729. The reversal of 1778728 is 8278771.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a d-powerful number, because it can be written as 1 + 7² + 7⁷ + 8 + 7⁷ + 2¹⁷ + 8³ .

It is not an unprimeable number, because it can be changed into a prime (1778729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 598 + ... + 1978.

It is an arithmetic number, because the mean of its divisors is an integer number (124380).

2^1778728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1778728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1990080).

1778728 is an abundant number, since it is smaller than the sum of its proper divisors (2201432).

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

1778728 is a wasteful number, since it uses less digits than its factorization.

1778728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417 (or 1413 counting only the distinct ones).

The product of its digits is 43904, while the sum is 40.

The square root of 1778728 is about 1333.6896190643. The cubic root of 1778728 is about 121.1629523658.

The spelling of 1778728 in words is "one million, seven hundred seventy-eight thousand, seven hundred twenty-eight".