28136729 has 4 divisors (see below), whose sum is σ = 28217700. Its totient is φ = 28055760.

The previous prime is 28136711. The next prime is 28136737. The reversal of 28136729 is 92763182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 92763182 = 2 ⋅46381591.

It can be written as a sum of positive squares in 2 ways, for example, as 8111104 + 20025625 = 2848^2 + 4475^2 .

It is a cyclic number.

It is not a de Polignac number, because 28136729 - 2¹⁶ = 28071193 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28136692 and 28136701.

It is not an unprimeable number, because it can be changed into a prime (28136029) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 39962 + ... + 40659.

It is an arithmetic number, because the mean of its divisors is an integer number (7054425).

Almost surely, 2^28136729 is an apocalyptic number.

It is an amenable number.

28136729 is a deficient number, since it is larger than the sum of its proper divisors (80971).

28136729 is an equidigital number, since it uses as much as digits as its factorization.

28136729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80970.

The product of its digits is 36288, while the sum is 38.

The square root of 28136729 is about 5304.4065643576. The cubic root of 28136729 is about 304.1523683610.

The spelling of 28136729 in words is "twenty-eight million, one hundred thirty-six thousand, seven hundred twenty-nine".