28780438 has 8 divisors (see below), whose sum is σ = 43500600. Its totient is φ = 14280240.

The previous prime is 28780417. The next prime is 28780463. The reversal of 28780438 is 83408782.

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

It is a super-2 number, since 2×28780438² = 1656627222943688, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28780438.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54663 + ... + 55186.

It is an arithmetic number, because the mean of its divisors is an integer number (5437575).

Almost surely, 2^28780438 is an apocalyptic number.

28780438 is a deficient number, since it is larger than the sum of its proper divisors (14720162).

28780438 is a wasteful number, since it uses less digits than its factorization.

28780438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109982.

The product of its (nonzero) digits is 86016, while the sum is 40.

The square root of 28780438 is about 5364.7402546628. The cubic root of 28780438 is about 306.4543565665.

The spelling of 28780438 in words is "twenty-eight million, seven hundred eighty thousand, four hundred thirty-eight".