28391505 has 16 divisors (see below), whose sum is σ = 46892544. Its totient is φ = 14653440.

The previous prime is 28391497. The next prime is 28391521. The reversal of 28391505 is 50519382.

It is not a de Polignac number, because 28391505 - 2³ = 28391497 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30064 + ... + 30993.

It is an arithmetic number, because the mean of its divisors is an integer number (2930784).

Almost surely, 2^28391505 is an apocalyptic number.

It is an amenable number.

28391505 is a deficient number, since it is larger than the sum of its proper divisors (18501039).

28391505 is a wasteful number, since it uses less digits than its factorization.

28391505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61096.

The product of its (nonzero) digits is 10800, while the sum is 33.

The square root of 28391505 is about 5328.3679490065. The cubic root of 28391505 is about 305.0676370645.

The spelling of 28391505 in words is "twenty-eight million, three hundred ninety-one thousand, five hundred five".