1721328 has 80 divisors (see below), whose sum is σ = 5237760. Its totient is φ = 476928.

The previous prime is 1721327. The next prime is 1721339. The reversal of 1721328 is 8231271.

It is a Harshad number since it is a multiple of its sum of digits (24).

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

Its product of digits (672) is a multiple of the sum of its prime divisors (168).

It is a junction number, because it is equal to n+sod(n) for n = 1721298 and 1721307.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721323) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15738 + ... + 15846.

It is an arithmetic number, because the mean of its divisors is an integer number (65472).

2^1721328 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 1721328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2618880).

1721328 is an abundant number, since it is smaller than the sum of its proper divisors (3516432).

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

1721328 is a wasteful number, since it uses less digits than its factorization.

1721328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 168 counting only the distinct ones).

The product of its digits is 672, while the sum is 24.

The square root of 1721328 is about 1311.9939024249. The cubic root of 1721328 is about 119.8453563523.

Adding to 1721328 its reverse (8231271), we get a palindrome (9952599).

The spelling of 1721328 in words is "one million, seven hundred twenty-one thousand, three hundred twenty-eight".