28103989 has 4 divisors (see below), whose sum is σ = 28121824. Its totient is φ = 28086156.

The previous prime is 28103947. The next prime is 28104007. The reversal of 28103989 is 98930182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28103989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28103909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6297 + ... + 9790.

It is an arithmetic number, because the mean of its divisors is an integer number (7030456).

Almost surely, 2^28103989 is an apocalyptic number.

It is an amenable number.

28103989 is a deficient number, since it is larger than the sum of its proper divisors (17835).

28103989 is a wasteful number, since it uses less digits than its factorization.

28103989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17834.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 28103989 is about 5301.3195527152. The cubic root of 28103989 is about 304.0343516410.

It can be divided in two parts, 28103 and 989, that added together give a palindrome (29092).

The spelling of 28103989 in words is "twenty-eight million, one hundred three thousand, nine hundred eighty-nine".