729028561 has 4 divisors (see below), whose sum is σ = 771912612. Its totient is φ = 686144512.

The previous prime is 729028513. The next prime is 729028567. The reversal of 729028561 is 165820927.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165820927 = 29 ⋅5717963.

It can be written as a sum of positive squares in 2 ways, for example, as 563777536 + 165251025 = 23744^2 + 12855^2 .

It is a cyclic number.

It is not a de Polignac number, because 729028561 - 2⁹ = 729028049 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (729028567) 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, 21442000 + ... + 21442033.

It is an arithmetic number, because the mean of its divisors is an integer number (192978153).

Almost surely, 2^729028561 is an apocalyptic number.

It is an amenable number.

729028561 is a deficient number, since it is larger than the sum of its proper divisors (42884051).

729028561 is a wasteful number, since it uses less digits than its factorization.

729028561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42884050.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 729028561 is about 27000.5289022271. The cubic root of 729028561 is about 900.0117533445.

The spelling of 729028561 in words is "seven hundred twenty-nine million, twenty-eight thousand, five hundred sixty-one".