28405409 has 2 divisors, whose sum is σ = 28405410. Its totient is φ = 28405408.

The previous prime is 28405367. The next prime is 28405423. The reversal of 28405409 is 90450482.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18037009 + 10368400 = 4247^2 + 3220^2 .

It is a cyclic number.

It is not a de Polignac number, because 28405409 - 2¹² = 28401313 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28405469) 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 as a sum of consecutive naturals, namely, 14202704 + 14202705.

It is an arithmetic number, because the mean of its divisors is an integer number (14202705).

Almost surely, 2^28405409 is an apocalyptic number.

It is an amenable number.

28405409 is a deficient number, since it is larger than the sum of its proper divisors (1).

28405409 is an equidigital number, since it uses as much as digits as its factorization.

28405409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 28405409 is about 5329.6725040100. The cubic root of 28405409 is about 305.1174285802.

The spelling of 28405409 in words is "twenty-eight million, four hundred five thousand, four hundred nine".