28261509 has 4 divisors (see below), whose sum is σ = 37682016. Its totient is φ = 18841004.

The previous prime is 28261507. The next prime is 28261537. The reversal of 28261509 is 90516282.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28261509 - 2¹ = 28261507 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28261509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28261507) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4710249 + ... + 4710254.

It is an arithmetic number, because the mean of its divisors is an integer number (9420504).

Almost surely, 2^28261509 is an apocalyptic number.

It is an amenable number.

28261509 is a deficient number, since it is larger than the sum of its proper divisors (9420507).

28261509 is an equidigital number, since it uses as much as digits as its factorization.

28261509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9420506.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 28261509 is about 5316.1554717672. The cubic root of 28261509 is about 304.6013208946.

The spelling of 28261509 in words is "twenty-eight million, two hundred sixty-one thousand, five hundred nine".