67728321 has 6 divisors (see below), whose sum is σ = 97829810. Its totient is φ = 45152208.

The previous prime is 67728319. The next prime is 67728343. The reversal of 67728321 is 12382776.

It can be written as a sum of positive squares in only one way, i.e., 61779600 + 5948721 = 7860^2 + 2439^2 .

It is not a de Polignac number, because 67728321 - 2¹ = 67728319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67728301) 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 5 ways as a sum of consecutive naturals, for example, 3762676 + ... + 3762693.

Almost surely, 2^67728321 is an apocalyptic number.

It is an amenable number.

67728321 is a deficient number, since it is larger than the sum of its proper divisors (30101489).

67728321 is a wasteful number, since it uses less digits than its factorization.

67728321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7525375 (or 7525372 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 67728321 is about 8229.7218057477. The cubic root of 67728321 is about 407.6212062449.

The spelling of 67728321 in words is "sixty-seven million, seven hundred twenty-eight thousand, three hundred twenty-one".