28417729 has 4 divisors (see below), whose sum is σ = 28487620. Its totient is φ = 28347840.

The previous prime is 28417723. The next prime is 28417733. The reversal of 28417729 is 92771482.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20007729 + 8410000 = 4473^2 + 2900^2 .

It is a cyclic number.

It is not a de Polignac number, because 28417729 - 2³ = 28417721 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28417691 and 28417700.

It is not an unprimeable number, because it can be changed into a prime (28417721) 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, 34332 + ... + 35149.

It is an arithmetic number, because the mean of its divisors is an integer number (7121905).

Almost surely, 2^28417729 is an apocalyptic number.

It is an amenable number.

28417729 is a deficient number, since it is larger than the sum of its proper divisors (69891).

28417729 is an equidigital number, since it uses as much as digits as its factorization.

28417729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69890.

The product of its digits is 56448, while the sum is 40.

The square root of 28417729 is about 5330.8281720573. The cubic root of 28417729 is about 305.1615340695.

The spelling of 28417729 in words is "twenty-eight million, four hundred seventeen thousand, seven hundred twenty-nine".