28409813 has 2 divisors, whose sum is σ = 28409814. Its totient is φ = 28409812.

The previous prime is 28409789. The next prime is 28409819. The reversal of 28409813 is 31890482.

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., 27804529 + 605284 = 5273^2 + 778^2 .

It is a cyclic number.

It is not a de Polignac number, because 28409813 - 2²² = 24215509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28409819) 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, 14204906 + 14204907.

It is an arithmetic number, because the mean of its divisors is an integer number (14204907).

Almost surely, 2^28409813 is an apocalyptic number.

It is an amenable number.

28409813 is a deficient number, since it is larger than the sum of its proper divisors (1).

28409813 is an equidigital number, since it uses as much as digits as its factorization.

28409813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 28409813 is about 5330.0856465914. The cubic root of 28409813 is about 305.1331963249.

The spelling of 28409813 in words is "twenty-eight million, four hundred nine thousand, eight hundred thirteen".