1721330 has 16 divisors (see below), whose sum is σ = 3336984. Its totient is φ = 635520.

The previous prime is 1721327. The next prime is 1721339. The reversal of 1721330 is 331271.

It can be written as a sum of positive squares in 4 ways, for example, as 1570009 + 151321 = 1253^2 + 389^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1721299 and 1721308.

It is not an unprimeable number, because it can be changed into a prime (1721339) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 6491 + ... + 6750.

2^1721330 is an apocalyptic number.

1721330 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1721330 is a deficient number, since it is larger than the sum of its proper divisors (1615654).

1721330 is a wasteful number, since it uses less digits than its factorization.

1721330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13261.

The product of its (nonzero) digits is 126, while the sum is 17.

The square root of 1721330 is about 1311.9946646233. The cubic root of 1721330 is about 119.8454027682.

The spelling of 1721330 in words is "one million, seven hundred twenty-one thousand, three hundred thirty".