28406309 has 2 divisors, whose sum is σ = 28406310. Its totient is φ = 28406308.

The previous prime is 28406291. The next prime is 28406327. The reversal of 28406309 is 90360482.

It is a balanced prime because it is at equal distance from previous prime (28406291) and next prime (28406327).

It can be written as a sum of positive squares in only one way, i.e., 28058209 + 348100 = 5297^2 + 590^2 .

It is a cyclic number.

It is not a de Polignac number, because 28406309 - 2¹⁶ = 28340773 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28406369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14203154 + 14203155.

It is an arithmetic number, because the mean of its divisors is an integer number (14203155).

Almost surely, 2^28406309 is an apocalyptic number.

It is an amenable number.

28406309 is a deficient number, since it is larger than the sum of its proper divisors (1).

28406309 is an equidigital number, since it uses as much as digits as its factorization.

28406309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 28406309 is about 5329.7569362964. The cubic root of 28406309 is about 305.1206510038.

The spelling of 28406309 in words is "twenty-eight million, four hundred six thousand, three hundred nine".