28979989 has 4 divisors (see below), whose sum is σ = 29686860. Its totient is φ = 28273120.

The previous prime is 28979983. The next prime is 28980013. The reversal of 28979989 is 98997982.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14311089 + 14668900 = 3783^2 + 3830^2 .

It is a cyclic number.

It is not a de Polignac number, because 28979989 - 2⁵ = 28979957 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 (28979983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 353374 + ... + 353455.

It is an arithmetic number, because the mean of its divisors is an integer number (7421715).

Almost surely, 2^28979989 is an apocalyptic number.

It is an amenable number.

28979989 is a deficient number, since it is larger than the sum of its proper divisors (706871).

28979989 is an equidigital number, since it uses as much as digits as its factorization.

28979989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706870.

The product of its digits is 5878656, while the sum is 61.

The square root of 28979989 is about 5383.3065118011. The cubic root of 28979989 is about 307.1609994898.

The spelling of 28979989 in words is "twenty-eight million, nine hundred seventy-nine thousand, nine hundred eighty-nine".