1721424 has 20 divisors (see below), whose sum is σ = 4447136. Its totient is φ = 573792.

The previous prime is 1721417. The next prime is 1721441. The reversal of 1721424 is 4241271.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 1721424.

It is a congruent number.

It is an unprimeable number.

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, 17884 + ... + 17979.

2^1721424 is an apocalyptic number.

It is an amenable number.

1721424 is an abundant number, since it is smaller than the sum of its proper divisors (2725712).

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

1721424 is a wasteful number, since it uses less digits than its factorization.

1721424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35874 (or 35868 counting only the distinct ones).

The product of its digits is 448, while the sum is 21.

The square root of 1721424 is about 1312.0304874507. The cubic root of 1721424 is about 119.8475842718.

Adding to 1721424 its reverse (4241271), we get a palindrome (5962695).

It can be divided in two parts, 1721 and 424, that added together give a triangular number (2145 = T₆₅).

The spelling of 1721424 in words is "one million, seven hundred twenty-one thousand, four hundred twenty-four".