728121173 has 16 divisors (see below), whose sum is σ = 845544000. Its totient is φ = 621198720.

The previous prime is 728121167. The next prime is 728121179. The reversal of 728121173 is 371121827.

It is an interprime number because it is at equal distance from previous prime (728121167) and next prime (728121179).

It is a cyclic number.

It is not a de Polignac number, because 728121173 - 2¹⁴ = 728104789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (728121179) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25823 + ... + 46076.

It is an arithmetic number, because the mean of its divisors is an integer number (52846500).

Almost surely, 2^728121173 is an apocalyptic number.

It is an amenable number.

728121173 is a deficient number, since it is larger than the sum of its proper divisors (117422827).

728121173 is a wasteful number, since it uses less digits than its factorization.

728121173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71972.

The product of its digits is 4704, while the sum is 32.

The square root of 728121173 is about 26983.7205181198. The cubic root of 728121173 is about 899.6381973721.

It can be divided in two parts, 72812117 and 3, that multiplied together give a triangular number (218436351 = T₂₀₉₀₁).

The spelling of 728121173 in words is "seven hundred twenty-eight million, one hundred twenty-one thousand, one hundred seventy-three".