28856729 has 4 divisors (see below), whose sum is σ = 31480080. Its totient is φ = 26233380.

The previous prime is 28856719. The next prime is 28856749. The reversal of 28856729 is 92765882.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28856729 - 2⁴ = 28856713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28856719) 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, 1311659 + ... + 1311680.

It is an arithmetic number, because the mean of its divisors is an integer number (7870020).

Almost surely, 2^28856729 is an apocalyptic number.

It is an amenable number.

28856729 is a deficient number, since it is larger than the sum of its proper divisors (2623351).

28856729 is a wasteful number, since it uses less digits than its factorization.

28856729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2623350.

The product of its digits is 483840, while the sum is 47.

The square root of 28856729 is about 5371.8459583275. The cubic root of 28856729 is about 306.7249000681.

The spelling of 28856729 in words is "twenty-eight million, eight hundred fifty-six thousand, seven hundred twenty-nine".