28990305 has 40 divisors (see below), whose sum is σ = 53108352. Its totient is φ = 15122592.

The previous prime is 28990289. The next prime is 28990307. The reversal of 28990305 is 50309982.

28990305 is a nontrivial binomial coefficient, being equal to C(7615, 2).

It is not a de Polignac number, because 28990305 - 2⁴ = 28990289 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28990305.

It is not an unprimeable number, because it can be changed into a prime (28990307) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 18274 + ... + 19796.

Almost surely, 2^28990305 is an apocalyptic number.

28990305 is the 7614-th triangular number.

It is an amenable number.

28990305 is a deficient number, since it is larger than the sum of its proper divisors (24118047).

28990305 is a wasteful number, since it uses less digits than its factorization.

28990305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1587 (or 1578 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 28990305 is about 5384.2645737371. The cubic root of 28990305 is about 307.1974418427.

The spelling of 28990305 in words is "twenty-eight million, nine hundred ninety thousand, three hundred five".