28690509 has 16 divisors (see below), whose sum is σ = 41022720. Its totient is φ = 17771520.

The previous prime is 28690507. The next prime is 28690517. The reversal of 28690509 is 90509682.

It is a happy number.

28690509 is nontrivially palindromic in base 12.

It is not a de Polignac number, because 28690509 - 2¹ = 28690507 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28690507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 469 + ... + 7589.

It is an arithmetic number, because the mean of its divisors is an integer number (2563920).

Almost surely, 2^28690509 is an apocalyptic number.

It is an amenable number.

28690509 is a deficient number, since it is larger than the sum of its proper divisors (12332211).

28690509 is a wasteful number, since it uses less digits than its factorization.

28690509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7220.

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 28690509 is about 5356.3522102267. The cubic root of 28690509 is about 306.1348352763.

The spelling of 28690509 in words is "twenty-eight million, six hundred ninety thousand, five hundred nine".