28917729 has 24 divisors (see below), whose sum is σ = 44073120. Its totient is φ = 18942336.

The previous prime is 28917719. The next prime is 28917743. The reversal of 28917729 is 92771982.

It is not a de Polignac number, because 28917729 - 2¹⁹ = 28393441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28917719) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13329 + ... + 15345.

It is an arithmetic number, because the mean of its divisors is an integer number (1836380).

Almost surely, 2^28917729 is an apocalyptic number.

It is an amenable number.

28917729 is a deficient number, since it is larger than the sum of its proper divisors (15155391).

28917729 is an equidigital number, since it uses as much as digits as its factorization.

28917729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2091 (or 2079 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 28917729 is about 5377.5207112572. The cubic root of 28917729 is about 306.9408756969.

It can be divided in two parts, 28917 and 729, that added together give a triangular number (29646 = T₂₄₃).

The spelling of 28917729 in words is "twenty-eight million, nine hundred seventeen thousand, seven hundred twenty-nine".