30028781 has 2 divisors, whose sum is σ = 30028782. Its totient is φ = 30028780.

The previous prime is 30028763. The next prime is 30028813. The reversal of 30028781 is 18782003.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28249225 + 1779556 = 5315^2 + 1334^2 .

It is a cyclic number.

It is not a de Polignac number, because 30028781 - 2¹⁴ = 30012397 is a prime.

It is a super-3 number, since 3×30028781³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30028711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15014390 + 15014391.

It is an arithmetic number, because the mean of its divisors is an integer number (15014391).

Almost surely, 2^30028781 is an apocalyptic number.

It is an amenable number.

30028781 is a deficient number, since it is larger than the sum of its proper divisors (1).

30028781 is an equidigital number, since it uses as much as digits as its factorization.

30028781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 30028781 is about 5479.8522790309. The cubic root of 30028781 is about 310.8225846793.

The spelling of 30028781 in words is "thirty million, twenty-eight thousand, seven hundred eighty-one".