28432309 has 2 divisors, whose sum is σ = 28432310. Its totient is φ = 28432308.

The previous prime is 28432307. The next prime is 28432319. The reversal of 28432309 is 90323482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28408900 + 23409 = 5330^2 + 153^2 .

It is a cyclic number.

It is not a de Polignac number, because 28432309 - 2¹ = 28432307 is a prime.

Together with 28432307, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28432307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14216154 + 14216155.

It is an arithmetic number, because the mean of its divisors is an integer number (14216155).

Almost surely, 2^28432309 is an apocalyptic number.

It is an amenable number.

28432309 is a deficient number, since it is larger than the sum of its proper divisors (1).

28432309 is an equidigital number, since it uses as much as digits as its factorization.

28432309 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 31.

The square root of 28432309 is about 5332.1955140448. The cubic root of 28432309 is about 305.2137138722.

The spelling of 28432309 in words is "twenty-eight million, four hundred thirty-two thousand, three hundred nine".