28319813 has 2 divisors, whose sum is σ = 28319814. Its totient is φ = 28319812.

The previous prime is 28319789. The next prime is 28319821. The reversal of 28319813 is 31891382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24186724 + 4133089 = 4918^2 + 2033^2 .

It is a cyclic number.

It is not a de Polignac number, because 28319813 - 2⁶ = 28319749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28319873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14159906 + 14159907.

It is an arithmetic number, because the mean of its divisors is an integer number (14159907).

Almost surely, 2^28319813 is an apocalyptic number.

It is an amenable number.

28319813 is a deficient number, since it is larger than the sum of its proper divisors (1).

28319813 is an equidigital number, since it uses as much as digits as its factorization.

28319813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 28319813 is about 5321.6363085051. The cubic root of 28319813 is about 304.8106430117.

The spelling of 28319813 in words is "twenty-eight million, three hundred nineteen thousand, eight hundred thirteen".