28409857 has 24 divisors (see below), whose sum is σ = 34801920. Its totient is φ = 23093280.

The previous prime is 28409833. The next prime is 28409861. The reversal of 28409857 is 75890482.

It is not a de Polignac number, because 28409857 - 2⁷ = 28409729 is a prime.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28409867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89463 + ... + 89779.

It is an arithmetic number, because the mean of its divisors is an integer number (1450080).

It is a Proth number, since it is equal to 867 ⋅ 2¹⁵ + 1 and 867 < 2¹⁵.

Almost surely, 2^28409857 is an apocalyptic number.

It is an amenable number.

28409857 is a deficient number, since it is larger than the sum of its proper divisors (6392063).

28409857 is a wasteful number, since it uses less digits than its factorization.

28409857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 43.

The square root of 28409857 is about 5330.0897741032. The cubic root of 28409857 is about 305.1333538510.

The spelling of 28409857 in words is "twenty-eight million, four hundred nine thousand, eight hundred fifty-seven".