67728509 has 2 divisors, whose sum is σ = 67728510. Its totient is φ = 67728508.

The previous prime is 67728503. The next prime is 67728511. The reversal of 67728509 is 90582776.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34987225 + 32741284 = 5915^2 + 5722^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-67728509 is a prime.

Together with 67728511, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 67728509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67728503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33864254 + 33864255.

It is an arithmetic number, because the mean of its divisors is an integer number (33864255).

Almost surely, 2^67728509 is an apocalyptic number.

It is an amenable number.

67728509 is a deficient number, since it is larger than the sum of its proper divisors (1).

67728509 is an equidigital number, since it uses as much as digits as its factorization.

67728509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 211680, while the sum is 44.

The square root of 67728509 is about 8229.7332277541. The cubic root of 67728509 is about 407.6215834023.

The spelling of 67728509 in words is "sixty-seven million, seven hundred twenty-eight thousand, five hundred nine".