28780965 has 12 divisors (see below), whose sum is σ = 49887084. Its totient is φ = 15349824.

The previous prime is 28780951. The next prime is 28781003. The reversal of 28780965 is 56908782.

It can be written as a sum of positive squares in 2 ways, for example, as 4485924 + 24295041 = 2118^2 + 4929^2 .

It is not a de Polignac number, because 28780965 - 2⁵ = 28780933 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 639577 = 28780965 / (2 + 8 + 7 + 8 + 0 + 9 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 28780965.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 319744 + ... + 319833.

It is an arithmetic number, because the mean of its divisors is an integer number (4157257).

Almost surely, 2^28780965 is an apocalyptic number.

It is an amenable number.

28780965 is a deficient number, since it is larger than the sum of its proper divisors (21106119).

28780965 is a wasteful number, since it uses less digits than its factorization.

28780965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639588 (or 639585 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 28780965 is about 5364.7893714479. The cubic root of 28780965 is about 306.4562270553.

The spelling of 28780965 in words is "twenty-eight million, seven hundred eighty thousand, nine hundred sixty-five".