28279509 has 16 divisors (see below), whose sum is σ = 38778432. Its totient is φ = 18321408.

The previous prime is 28279499. The next prime is 28279519. The reversal of 28279509 is 90597282.

It is an interprime number because it is at equal distance from previous prime (28279499) and next prime (28279519).

It is not a de Polignac number, because 28279509 - 2¹² = 28275413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28279519) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32727 + ... + 33579.

It is an arithmetic number, because the mean of its divisors is an integer number (2423652).

Almost surely, 2^28279509 is an apocalyptic number.

It is an amenable number.

28279509 is a deficient number, since it is larger than the sum of its proper divisors (10498923).

28279509 is a wasteful number, since it uses less digits than its factorization.

28279509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156.

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 28279509 is about 5317.8481550341. The cubic root of 28279509 is about 304.6659749107.

The spelling of 28279509 in words is "twenty-eight million, two hundred seventy-nine thousand, five hundred nine".