28990309 has 2 divisors, whose sum is σ = 28990310. Its totient is φ = 28990308.

The previous prime is 28990307. The next prime is 28990319. The reversal of 28990309 is 90309982.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20884900 + 8105409 = 4570^2 + 2847^2 .

It is a cyclic number.

It is not a de Polignac number, because 28990309 - 2¹ = 28990307 is a prime.

It is a super-3 number, since 3×28990309³ (a number of 23 digits) contains 333 as substring.

Together with 28990307, 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 (28990307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14495154 + 14495155.

It is an arithmetic number, because the mean of its divisors is an integer number (14495155).

Almost surely, 2^28990309 is an apocalyptic number.

It is an amenable number.

28990309 is a deficient number, since it is larger than the sum of its proper divisors (1).

28990309 is an equidigital number, since it uses as much as digits as its factorization.

28990309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 28990309 is about 5384.2649451898. The cubic root of 28990309 is about 307.1974559715.

The spelling of 28990309 in words is "twenty-eight million, nine hundred ninety thousand, three hundred nine".