28721113 has 2 divisors, whose sum is σ = 28721114. Its totient is φ = 28721112.

The previous prime is 28721093. The next prime is 28721129. The reversal of 28721113 is 31112782.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18429849 + 10291264 = 4293^2 + 3208^2 .

It is a cyclic number.

It is not a de Polignac number, because 28721113 - 2⁵ = 28721081 is a prime.

It is not a weakly prime, because it can be changed into another prime (28721713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14360556 + 14360557.

It is an arithmetic number, because the mean of its divisors is an integer number (14360557).

Almost surely, 2^28721113 is an apocalyptic number.

It is an amenable number.

28721113 is a deficient number, since it is larger than the sum of its proper divisors (1).

28721113 is an equidigital number, since it uses as much as digits as its factorization.

28721113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 25.

The square root of 28721113 is about 5359.2082437614. The cubic root of 28721113 is about 306.2436473484.

Adding to 28721113 its reverse (31112782), we get a palindrome (59833895).

The spelling of 28721113 in words is "twenty-eight million, seven hundred twenty-one thousand, one hundred thirteen".