1028720 has 80 divisors (see below), whose sum is σ = 2999808. Its totient is φ = 318720.

The previous prime is 1028683. The next prime is 1028737. The reversal of 1028720 is 278201.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 1028692 and 1028701.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6077 + ... + 6243.

2^1028720 is an apocalyptic number.

1028720 is a gapful number since it is divisible by the number (10) 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 1028720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1499904).

1028720 is an abundant number, since it is smaller than the sum of its proper divisors (1971088).

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

1028720 is a wasteful number, since it uses less digits than its factorization.

1028720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198 (or 192 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 1028720 is about 1014.2583497315. The cubic root of 1028720 is about 100.9483119507.

The spelling of 1028720 in words is "one million, twenty-eight thousand, seven hundred twenty".