28907521 has 2 divisors, whose sum is σ = 28907522. Its totient is φ = 28907520.

The previous prime is 28907509. The next prime is 28907551. The reversal of 28907521 is 12570982.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25806400 + 3101121 = 5080^2 + 1761^2 .

It is a cyclic number.

It is not a de Polignac number, because 28907521 - 2¹³ = 28899329 is a prime.

It is not a weakly prime, because it can be changed into another prime (28907551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14453760 + 14453761.

It is an arithmetic number, because the mean of its divisors is an integer number (14453761).

Almost surely, 2^28907521 is an apocalyptic number.

It is an amenable number.

28907521 is a deficient number, since it is larger than the sum of its proper divisors (1).

28907521 is an equidigital number, since it uses as much as digits as its factorization.

28907521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 28907521 is about 5376.5714912014. The cubic root of 28907521 is about 306.9047545892.

The spelling of 28907521 in words is "twenty-eight million, nine hundred seven thousand, five hundred twenty-one".