728291689 has 4 divisors (see below), whose sum is σ = 730022020. Its totient is φ = 726561360.

The previous prime is 728291653. The next prime is 728291699. The reversal of 728291689 is 986192827.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 986192827 = 23 ⋅42877949.

It can be written as a sum of positive squares in 2 ways, for example, as 89870400 + 638421289 = 9480^2 + 25267^2 .

It is a cyclic number.

It is not a de Polignac number, because 728291689 - 2²¹ = 726194537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (728291639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 864534 + ... + 865375.

It is an arithmetic number, because the mean of its divisors is an integer number (182505505).

Almost surely, 2^728291689 is an apocalyptic number.

It is an amenable number.

728291689 is a deficient number, since it is larger than the sum of its proper divisors (1730331).

728291689 is a wasteful number, since it uses less digits than its factorization.

728291689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1730330.

The product of its digits is 870912, while the sum is 52.

The square root of 728291689 is about 26986.8799419273. The cubic root of 728291689 is about 899.7084195362.

The spelling of 728291689 in words is "seven hundred twenty-eight million, two hundred ninety-one thousand, six hundred eighty-nine".