1728905805 has 96 divisors (see below), whose sum is σ = 3394879488. Its totient is φ = 806371200.

The previous prime is 1728905777. The next prime is 1728905819. The reversal of 1728905805 is 5085098271.

It is a happy number.

It is not a de Polignac number, because 1728905805 - 2¹³ = 1728897613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 4710732 + ... + 4711098.

It is an arithmetic number, because the mean of its divisors is an integer number (35363328).

Almost surely, 2^1728905805 is an apocalyptic number.

1728905805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1728905805 is a deficient number, since it is larger than the sum of its proper divisors (1665973683).

1728905805 is a wasteful number, since it uses less digits than its factorization.

1728905805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727 (or 724 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 45.

The square root of 1728905805 is about 41580.1130950843. The cubic root of 1728905805 is about 1200.2096404569.

The spelling of 1728905805 in words is "one billion, seven hundred twenty-eight million, nine hundred five thousand, eight hundred five".