28780065 has 36 divisors (see below), whose sum is σ = 53016444. Its totient is φ = 14439936.

The previous prime is 28780057. The next prime is 28780067. The reversal of 28780065 is 56008782.

It can be written as a sum of positive squares in 6 ways, for example, as 8503056 + 20277009 = 2916^2 + 4503^2 .

It is not a de Polignac number, because 28780065 - 2³ = 28780057 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28780067) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 11899 + ... + 14111.

It is an arithmetic number, because the mean of its divisors is an integer number (1472679).

Almost surely, 2^28780065 is an apocalyptic number.

It is an amenable number.

28780065 is a deficient number, since it is larger than the sum of its proper divisors (24236379).

28780065 is a wasteful number, since it uses less digits than its factorization.

28780065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2258 (or 2238 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 28780065 is about 5364.7054905186. The cubic root of 28780065 is about 306.4530326584.

The spelling of 28780065 in words is "twenty-eight million, seven hundred eighty thousand, sixty-five".