28611309 has 8 divisors (see below), whose sum is σ = 38264992. Its totient is φ = 19015920.

The previous prime is 28611299. The next prime is 28611311. The reversal of 28611309 is 90311682.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28611309 - 2¹¹ = 28609261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28611409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13414 + ... + 15399.

It is an arithmetic number, because the mean of its divisors is an integer number (4783124).

Almost surely, 2^28611309 is an apocalyptic number.

It is an amenable number.

28611309 is a deficient number, since it is larger than the sum of its proper divisors (9653683).

28611309 is a wasteful number, since it uses less digits than its factorization.

28611309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29147.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 28611309 is about 5348.9540098976. The cubic root of 28611309 is about 305.8528811356.

It can be divided in two parts, 28611 and 309, that added together give a triangular number (28920 = T₂₄₀).

The spelling of 28611309 in words is "twenty-eight million, six hundred eleven thousand, three hundred nine".