28180509 has 32 divisors (see below), whose sum is σ = 45815040. Its totient is φ = 15040512.

The previous prime is 28180501. The next prime is 28180513. The reversal of 28180509 is 90508182.

It is a happy number.

It is not a de Polignac number, because 28180509 - 2³ = 28180501 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28180509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28180501) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 68697 + ... + 69105.

It is an arithmetic number, because the mean of its divisors is an integer number (1431720).

Almost surely, 2^28180509 is an apocalyptic number.

It is an amenable number.

28180509 is a deficient number, since it is larger than the sum of its proper divisors (17634531).

28180509 is a wasteful number, since it uses less digits than its factorization.

28180509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 629.

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 28180509 is about 5308.5317179047. The cubic root of 28180509 is about 304.3100376044.

The spelling of 28180509 in words is "twenty-eight million, one hundred eighty thousand, five hundred nine".