728121999 has 8 divisors (see below), whose sum is σ = 1059086592. Its totient is φ = 441286040.

The previous prime is 728121991. The next prime is 728122033. The reversal of 728121999 is 999121827.

728121999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 728121999 - 2³ = 728121991 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (728121991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11032119 + ... + 11032184.

It is an arithmetic number, because the mean of its divisors is an integer number (132385824).

Almost surely, 2^728121999 is an apocalyptic number.

728121999 is a deficient number, since it is larger than the sum of its proper divisors (330964593).

728121999 is a wasteful number, since it uses less digits than its factorization.

728121999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22064317.

The product of its digits is 163296, while the sum is 48.

The square root of 728121999 is about 26983.7358236401. The cubic root of 728121999 is about 899.6385375632.

The spelling of 728121999 in words is "seven hundred twenty-eight million, one hundred twenty-one thousand, nine hundred ninety-nine".