28780405 has 16 divisors (see below), whose sum is σ = 36694080. Its totient is φ = 21595392.

The previous prime is 28780397. The next prime is 28780417. The reversal of 28780405 is 50408782.

It is a cyclic number.

It is not a de Polignac number, because 28780405 - 2³ = 28780397 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46186 + ... + 46804.

It is an arithmetic number, because the mean of its divisors is an integer number (2293380).

Almost surely, 2^28780405 is an apocalyptic number.

It is an amenable number.

28780405 is a deficient number, since it is larger than the sum of its proper divisors (7913675).

28780405 is a wasteful number, since it uses less digits than its factorization.

28780405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1188.

The product of its (nonzero) digits is 17920, while the sum is 34.

The square root of 28780405 is about 5364.7371790238. The cubic root of 28780405 is about 306.4542394384.

The spelling of 28780405 in words is "twenty-eight million, seven hundred eighty thousand, four hundred five".