28520091 has 12 divisors (see below), whose sum is σ = 41811432. Its totient is φ = 18729216.

The previous prime is 28520059. The next prime is 28520099. The reversal of 28520091 is 19002582.

It is not a de Polignac number, because 28520091 - 2⁵ = 28520059 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28520099) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23046 + ... + 24251.

It is an arithmetic number, because the mean of its divisors is an integer number (3484286).

Almost surely, 2^28520091 is an apocalyptic number.

28520091 is a deficient number, since it is larger than the sum of its proper divisors (13291341).

28520091 is a wasteful number, since it uses less digits than its factorization.

28520091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47370 (or 47367 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 28520091 is about 5340.4204890626. The cubic root of 28520091 is about 305.5274970942.

The spelling of 28520091 in words is "twenty-eight million, five hundred twenty thousand, ninety-one".