1728021306 has 32 divisors (see below), whose sum is σ = 3857914368. Its totient is φ = 511464240.

The previous prime is 1728021293. The next prime is 1728021307. The reversal of 1728021306 is 6031208271.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1728021307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 301606 + ... + 307281.

It is an arithmetic number, because the mean of its divisors is an integer number (120559824).

Almost surely, 2^1728021306 is an apocalyptic number.

1728021306 is an abundant number, since it is smaller than the sum of its proper divisors (2129893062).

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

1728021306 is a wasteful number, since it uses less digits than its factorization.

1728021306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608946.

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 1728021306 is about 41569.4756522138. The cubic root of 1728021306 is about 1200.0049319242.

Adding to 1728021306 its reverse (6031208271), we get a palindrome (7759229577).

It can be divided in two parts, 17280 and 21306, that multiplied together give a triangular number (368167680 = T₂₇₁₃₅).

The spelling of 1728021306 in words is "one billion, seven hundred twenty-eight million, twenty-one thousand, three hundred six".