1729729728 has 70 divisors (see below), whose sum is σ = 5127476156. Its totient is φ = 576574848.

The previous prime is 1729729699. The next prime is 1729729747. The reversal of 1729729728 is 8279279271.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

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 9 ways as a sum of consecutive naturals, for example, 161650 + ... + 172017.

Almost surely, 2^1729729728 is an apocalyptic number.

1729729728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1729729728 is an abundant number, since it is smaller than the sum of its proper divisors (3397746428).

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

1729729728 is an equidigital number, since it uses as much as digits as its factorization.

1729729728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333691 (or 333672 counting only the distinct ones).

The product of its digits is 1778112, while the sum is 54.

The square root of 1729729728 is about 41590.0195720079. The cubic root of 1729729728 is about 1200.4002664741.

The spelling of 1729729728 in words is "one billion, seven hundred twenty-nine million, seven hundred twenty-nine thousand, seven hundred twenty-eight".