728405505 has 24 divisors (see below), whose sum is σ = 1264077672. Its totient is φ = 388018944.

The previous prime is 728405473. The next prime is 728405507. The reversal of 728405505 is 505504827.

It is a happy number.

728405505 is a `hidden beast` number, since 72 + 84 + 0 + 5 + 505 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 256256064 + 472149441 = 16008^2 + 21729^2 .

It is not a de Polignac number, because 728405505 - 2⁵ = 728405473 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 728405505.

It is not an unprimeable number, because it can be changed into a prime (728405507) 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 in 23 ways as a sum of consecutive naturals, for example, 30237 + ... + 48693.

It is an arithmetic number, because the mean of its divisors is an integer number (52669903).

Almost surely, 2^728405505 is an apocalyptic number.

It is an amenable number.

728405505 is a deficient number, since it is larger than the sum of its proper divisors (535672167).

728405505 is a wasteful number, since it uses less digits than its factorization.

728405505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19345 (or 19342 counting only the distinct ones).

The product of its (nonzero) digits is 56000, while the sum is 36.

The square root of 728405505 is about 26988.9885879408. The cubic root of 728405505 is about 899.7552853187.

The spelling of 728405505 in words is "seven hundred twenty-eight million, four hundred five thousand, five hundred five".